cr50: wake from deep sleep on rising edge of AP UART
cr50: wake from deep sleep on rising edge of AP UART

The AP UART is used to detect if the device is in s0. When it is cr50
should not be in deep sleep for any reason. This change makes DIOA5 a
wake pin before entering deep sleep.

BUG=chrome-os-partner:56100
BRANCH=none
TEST=make buildall

Change-Id: Icb57824c0ca1421f5f508fce7cf5609010b91e32
Signed-off-by: Mary Ruthven <81380f3403fed74252e92df3ed012a1819ec6296@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/388793
Reviewed-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec