glimmer: set brightness lowest level PWM duty to 5%

set min_visible_backlight_level to 196(/max 3906)

BUG=chrome-os-partner:27610
TEST=emerge-glimmer chromeos-bsp-glimmer
Verify min_visible_backlight_level exists in build.

Change-Id: I4a6ac1b75c8bc4297c4ac123f6773d51f4e6a783
Reviewed-on: https://chromium-review.googlesource.com/193186
Reviewed-by: Bernie Thompson <bhthompson@chromium.org>
Commit-Queue: Kevin Cheng <kevin.cheng@intel.com>
Tested-by: Kevin Cheng <kevin.cheng@intel.com>
(cherry picked from commit fb87e9fdd5e6102a22341dfa476a3cd51cd98c45)
Reviewed-on: https://chromium-review.googlesource.com/194207
Commit-Queue: Bernie Thompson <bhthompson@chromium.org>
Tested-by: Bernie Thompson <bhthompson@chromium.org>
3 files changed