Updated raylib input system (markdown)

raylib-input-system.md

@@ -43,7 +43,7 @@ MOUSE | - | Mouse inputs are actually mapped with TOUCH input
 GAMEPAD | Android NDK | Support *partially* implemented on `AndroidInputCallback()`
 TOUCH | Android NDK | Touch points registered on `AndroidInputCallback()`
 
-PLATFORM_RPI
+PLATFORM_DRM
 -------------
 Probably this platform inputs polling is the most complex one. Some input events are polled by multiple secondary threads.