mb/google/kahlee: Add getter function for GPIO array

Instead of getting the address of the GPIO function with an extern,
add a getter function and make the GPIO arrays static.

TEST=Build Grunt; Build & boot Kahlee

Change-Id: I3defcb66696459b915d7d4f43234d5c08ab7d417
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/22435
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marc Jones <marc@marcjonesconsulting.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
4 files changed