drm: debugfs: make drm_debugfs_create_files() never fail

drm: debugfs: make drm_debugfs_create_files() never fail

As stated before, there is no need to care if a debugfs function
succeeds or not, and no code logic in the kernel should ever change
based on a debugfs function return value, so make
drm_debugfs_create_files() never fail.  If it encounters an
odd/rare/impossible error (i.e. out of memory, or a duplicate debugfs
filename to be created), just keep on moving as if nothing improper had
happened.

Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Sean Paul <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]