Add an ANALOG button mapping

[lsvy97]

Problem: Some PS2 games support the analog controls, but they reset them to digital only at the start of the game. Ridge Racer V always does this, and the only way to use analog controls in this game is to press an ANALOG button in the game. This is how it works in standalone PCSX2, ANALOG can be mapped. But there is no option to map or toggle the "ANALOG" button in LRPS2 on Retroarch.

Solution: Add a mapping for the ANALOG button for LPRS2