soc/intel/xeon_sp: Make gsi_bases platform independent
This commit makes gsi_bases platform independent. It introduces two new
Kconfigs which set if there are IIO APICs on other devices than the PCH
or not, and where they do start.
Change-Id: I40db4a8fd90572757687f35bbd8eebd7229fc75a
Signed-off-by: Christian Walter <christian.walter@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65531
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>