{arch,cpu}/x86, drivers/intel: Restore cpu_index error handling

Previously cpu_index() always succeeded, but since commit 095c931
(src/arch/x86: Use core apic id to get cpu_index()) it is now possible
for it to indicate an error by returning -1. This commit adds error
handling for all calls to cpu_index(), and restores several checks that
were removed in commit 7c712bb (Fix code that would trip -Wtype-limits)
but are now needed.

Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Change-Id: I5436eed4cb5675f916924eb9670db04592a8b927
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32795
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/drivers/intel/fsp2_0/ppi/mp_service_ppi.c

@@ -45,6 +45,9 @@ static efi_return_status_t mp_get_processor_info(const
 	efi_uintn_t processor_number,
 	efi_processor_information *processor_info_buffer)
 {
+	if (cpu_index() < 0)
+		return FSP_DEVICE_ERROR;
+
 	if (processor_info_buffer == NULL)
 		return FSP_INVALID_PARAMETER;
 
@@ -68,6 +71,9 @@ static efi_return_status_t mp_startup_all_aps(const
 	efi_ap_procedure procedure, efi_boolean_t ignored3,
 	efi_uintn_t timeout_usec, void *argument)
 {
+	if (cpu_index() < 0)
+		return FSP_DEVICE_ERROR;
+
 	if (procedure == NULL)
 		return FSP_INVALID_PARAMETER;
 
@@ -85,6 +91,9 @@ static efi_return_status_t mp_startup_this_ap(const
 	efi_ap_procedure procedure, efi_uintn_t processor_number,
 	efi_uintn_t timeout_usec, void *argument)
 {
+	if (cpu_index() < 0)
+		return FSP_DEVICE_ERROR;
+
 	if (processor_number > get_cpu_count())
 		return FSP_NOT_FOUND;