drm/tegra: remove checks for debugfs functions return value

Since 987d65d0 (drm: debugfs: make
drm_debugfs_create_files() never fail) there is no need to check the
return value of drm_debugfs_create_files(). Therefore, remove the
return checks and error handling of the drm_debugfs_create_files()
function from various debugfs init functions in drm/tegra and have
them return 0 directly.

v2: remove conversion of tegra_debugfs_init() to void to avoid build
breakage.

References: https://lists.freedesktop.org/archives/dri-devel/2020-February/257183.html


Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.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/20200310133121.27913-2-wambui.karugax@gmail.com