Restore the backlight level on resume.  Some systems
need to explicitly restore the backlight level on
resume.

Fixes panel resume on my Trinity laptop and may fix the
following bugs:
https://bugs.freedesktop.org/show_bug.cgi?id=43829
https://bugzilla.kernel.org/show_bug.cgi?id=46241Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>