[rcore][drm] Disable touch position simulation from mouse movement for touchscreen devices #4842

[MULTidll]

Summary

• Touch positions are now reset to an invalid state ({-1, -1}) instead of zero in fuction PollInputEvents from src/platforms/rcore_drm.c file, which helps avoid unintended touch detections on DRM touchscreen devices.
• The mapping of mouse position to touch position is disabled for DRM touchscreen devices.

[raysan5]

@MULTidll Merging the change because I understand you are working on DRM with a touch display at the moment but I'm not sure about the -1 convention, default state is 0, and if finally adopted, it requires to be reviewed in all platforms, so this change conditions multiple other changes for platform consistency.

[MULTidll]

@raysan5 sure. yes indeed i understannd the usage of -1 convention would affect for other platforms I will try something if the issue can be rectified using the default 0 state , I would like to know if you have any suggestions to handle the issue in other way so that the default state is kept 0?

[MULTidll]

@raysan5 So I guess if (0, 0) is the default, making (0, 0) not to be counted as a valid touch unless a real touch event sets it to (0,0), but this assumes that a real touch at (0,0) is very rare to happen so we would be needing to handle that special case.