Fixed cmake warning

Author: jorisplusplus

firmware/components/driver_display_hub75/Kconfig

@@ -51,7 +51,7 @@ menu "Driver: HUB75 LED panel display"
 
 	config HUB75_DEFAULT_BRIGHTNESS
 		depends on DRIVER_HUB75_ENABLE
-		int "Default brightness, being a value between 0 and "
+		int "Default brightness, being a value between 0 and 30"
 		default 30
 
 	config HUB75_CLOCK_SPEED