cheza: Config the SPI flash size to 1MB
cheza: Config the SPI flash size to 1MB

The NPCX7M7WB has 1MB internal SPI flash. Config it correctly.

BRANCH=none
BUG=b:114686845
TEST=Checked the EC image size is 1MB. Ran flashrom to flash EC.

Change-Id: Ie0ed27f72019790cfeb283349ae28fd05dc9693a
Signed-off-by: Wai-Hong Tam <04b587fdf5845741a0c5a8b9cd59ca72d73ef8fc@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1215882
Tested-by: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Reviewed-by: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>

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