mainboard/google/kahlee: Update PCIe port map

- Grunt moved the EMMC chip to port 2, where Kahlee had the SD reader on
PCIe port 1, so move the OemCustomize file into the variant directory.
- Add comments in baseboard version so it's easier to understand.
- Update reset pins, put the definitions in gpio.h

BUG=b:70255003
TEST=Build and boot Kahlee.  Build Grunt.

Change-Id: I78ec72e9d6fd52b8ac75e7187bd01ee7ddc3ba2a
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/22750
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marc Jones <marc@marcjonesconsulting.com>
7 files changed