gs_usb: fix compat with AMD xHCI USB

[BenGardiner]

The AMD xHCI USB host is very very picky . About timings, and descriptors and ... well everything.

This commit gets RAMN gs_usb up to the strict requirements enforced by AMD xHCI. Still works on other Intel USB as well.

• Fix STM32 HAL USB PCD concurrency bug by adding IRQ-safe critical sections
• Handle lock failure edge case: re-enable IRQ before returning HAL_BUSY
• Move USB concurrency fix to usbd_conf.c with USER CODE block protection
• Fix USB PCD concurrency: add __HAL_LOCK with IRQ critical sections in HAL driver
• Fix EP2 OUT descriptor: wMaxPacketSize 128->64 for Full-Speed USB compliance
• Add IAD for GS_USB+DFU interfaces for AMD xHCI compatibility
• STALL unhandled USB control requests in composite Setup handler
• Add WARNING comments for AMD xHCI USB compatibility

[github-actions]

🔨 Build & Macro Coverage Report

Default Builds — Hex File Sizes

ECU	Debug (tag 15.0)	Debug (gsusb) (tag 15.0)	Release (tag 15.0)	Release (gsusb) (tag 15.0)
ECUA	482 KiB (494200 bytes)	496 KiB (508592 bytes)	314 KiB (322484 bytes)	323 KiB (331410 bytes)
ECUB	332 KiB (340532 bytes)	332 KiB (340532 bytes)	194 KiB (199306 bytes)	194 KiB (199306 bytes)
ECUC	312 KiB (320200 bytes)	312 KiB (320200 bytes)	173 KiB (178057 bytes)	173 KiB (178057 bytes)
ECUD	322 KiB (330640 bytes)	322 KiB (330640 bytes)	181 KiB (185549 bytes)	181 KiB (185549 bytes)

Macro Coverage Build Results

ECU	Variant	Macros Changed	Result	Hex Size	Warnings
ECUA	gsusb	+ENABLE_GSUSB −ENABLE_CDC	✅ Pass	266 KiB	0
ECUA	no_debug	−ENABLE_USB_DEBUG −ENABLE_JOYSTICK_CONTROLS −ENABLE_SCREEN −ENABLE_CHIP8 −GENERATE_RUNTIME_STATS	✅ Pass	223 KiB	1
ECUA	no_extras	−ENABLE_J1979 −ENABLE_MINICTF −ENABLE_CHIP8 −ENABLE_SCREEN −ENABLE_SPI	✅ Pass	233 KiB	1
ECUA	no_uds	−ENABLE_UDS −ENABLE_UDS_REPROGRAMMING	✅ Pass	271 KiB	1
ECUB	kwp	+ENABLE_KWP	✅ Pass	197 KiB	0
ECUB	no_dynamic_bitrate	−ENABLE_DYNAMIC_BITRATE	✅ Pass	194 KiB	0
ECUB	watchdog	+WATCHDOG_ENABLE	✅ Pass	195 KiB	0
ECUC	uart	+ENABLE_UART	✅ Pass	190 KiB	0

Source Code Compile Coverage

• Total .c source lines: 18024
• Lines compiled in ≥1 configuration: 16811 (~93%)
• ENABLE_ macro coverage: 19/21 (90.5%) macros tested in both ON and OFF states

Full ENABLE_ Macro Coverage Table

#	Macro	Tested ON	Tested OFF	Covered
1	ENABLE_ADC	default (ECUB, ECUC, ECUD)	default (ECUA)	✅
2	ENABLE_CDC	default (ECUA)	default (ECUB, ECUC, ECUD), variant: gsusb (ECUA)	✅
3	ENABLE_CHIP8	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug (ECUA), variant: no_extras (ECUA)	✅
4	ENABLE_DYNAMIC_BITRATE	default (ECUA, ECUB, ECUC, ECUD)	variant: no_dynamic_bitrate (ECUB)	✅
5	ENABLE_GSUSB	variant: gsusb (ECUA)	default (ECUA, ECUB, ECUC, ECUD)	✅
6	ENABLE_I2C	—	default (ECUA, ECUB, ECUC, ECUD)	⬜
7	ENABLE_J1979	default (ECUA, ECUB, ECUC, ECUD)	variant: no_extras (ECUA)	✅
8	ENABLE_JOYSTICK_CONTROLS	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug (ECUA)	✅
9	ENABLE_KWP	variant: kwp (ECUB)	default (ECUA, ECUB, ECUC, ECUD)	✅
10	ENABLE_MINICTF	default (ECUA, ECUD)	default (ECUB, ECUC), variant: no_extras (ECUA)	✅
11	ENABLE_SCREEN	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug (ECUA), variant: no_extras (ECUA)	✅
12	ENABLE_SPI	default (ECUA, ECUD)	default (ECUB, ECUC), variant: no_extras (ECUA)	✅
13	ENABLE_UART	variant: uart (ECUC)	default (ECUA, ECUB, ECUC, ECUD)	✅
14	ENABLE_UDS	default (ECUA, ECUB, ECUC, ECUD)	variant: no_uds (ECUA)	✅
15	ENABLE_UDS_REPROGRAMMING	default (ECUA, ECUB, ECUC, ECUD)	variant: no_uds (ECUA)	✅
16	ENABLE_USB	default (ECUA)	default (ECUB, ECUC, ECUD)	✅
17	ENABLE_USB_AUTODETECT	—	default (ECUA, ECUB, ECUC, ECUD)	⬜
18	ENABLE_USB_DEBUG	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug (ECUA)	✅
19	ENABLE_XCP	default (ECUB, ECUC, ECUD)	default (ECUA)	✅
20	GENERATE_RUNTIME_STATS	default (ECUA, ECUB, ECUC, ECUD)	variant: no_debug (ECUA)	✅
21	WATCHDOG_ENABLE	variant: watchdog (ECUB)	default (ECUA, ECUB, ECUC, ECUD)	✅