mainboard/google/reef: set SLP_S3_L assertion width to 28ms
The reef board needs at least ~28ms for its S0 rails to discharge
when S3 is entered. Because of the granularity in the chipset the
effective SLP_S3_L assertion width is 50ms.
BUG=chrome-os-partner:56581
Change-Id: I20514eb0825cd4bc2ee9276b648204b7bfd6a7b0
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/16327
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>