drm/omap: remove checks for return value of drm_debugfs functions

drm/omap: remove checks for return value of drm_debugfs functions

Since 987d65d01356 (drm: debugfs: make
drm_debugfs_create_files() never fail), there is no need to ever check
the return value for drm_debugfs_create_files(). Therefore remove the
checks for the return value and subsequent error handling in
omap_debugfs_init().

These changes also enables the changing of omap_debugfs_init() to return
0 directly.

v2: convert omap_debugfs_init() to return 0 instead of void to avoid
introduction of build issues and enable individual driver compilation.

References: https://lists.freedesktop.org/archives/dri-devel/2020-February/257183.html
Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200310133121.27913-14-wambui.karugax@gmail.com