The ICH7 SPIBAR offset and registers are different from later
generation.
ICH8 has a different offset from later generation.
ICH6 has no SPI controller.
Change-Id: I7691bce619089b15805114047bcb1fd121a5722b
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/17978
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
a5798a9b8f