vc/google/chromeos: Refactor GNVS init

Move the support code for filling ChromeOS GNVS from
acpi/chromeos-gnvs.c to vc/google/chromeos/gnvs.c.

Change-Id: I7e92206561812eb3dc69739df49b6c3a93853858
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50612
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Lance Zhao
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/vendorcode/google/chromeos/chromeos.h

@@ -29,6 +29,7 @@ void mainboard_prepare_cr50_reset(void);
 
 void cbmem_add_vpd_calibration_data(void);
 void chromeos_set_me_hash(u32*, int);
+void chromeos_set_ramoops(void *ram_oops, size_t size);
 
 /**
  * get_dsm_calibration_from_key - Gets value related to DSM calibration from VPD