sandybridge boards: Factor out MAX_CPUS

Also update autoport accordingly.

Change-Id: I12481363cf0e7afc54e2e339504f70632e8d72e2
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41839
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/autoport/sandybridge.go

@@ -89,8 +89,6 @@ func (i sandybridgemc) Scan(ctx Context, addr PCIDevData) {
 	KconfigBool["HAVE_ACPI_TABLES"] = true
 	KconfigBool["HAVE_ACPI_RESUME"] = true
 
-	KconfigInt["MAX_CPUS"] = 8
-
 	DSDTIncludes = append(DSDTIncludes, DSDTInclude{
 		File: "cpu/intel/common/acpi/cpu.asl",
 	})