Support reading the ACPI GPE status (on x86) to determine when
the cr50 is ready to return response data or is done processing
written data. If the interrupt is not defined by Kconfig then
it will continue to use the safe delay.
This was tested with reef hardware and a modified cr50 image
that generates interrupts at the intended points.
BUG=chrome-os-partner:53336
Change-Id: Ic8f805159650c45382cacac8840450a1f8b4d7a1
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/16672
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
94cc485338