device: Add support for multiple PCI segment groups

Add initial support for multiple PCI segment groups. Instead of
modifying secondary in the bus struct introduce a new segment_group
struct element and keep existing common code.

Since all platforms currently only use 1 segment this is not a
functional change. On platforms that support more than 1 segment the
segment has to be set when creating the PCI domain.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ied3313c41896362dd989ee2ab1b1bcdced840aa8
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79927
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
diff --git a/src/soc/intel/xeon_sp/uncore.c b/src/soc/intel/xeon_sp/uncore.c
index 66f63d5..c8e1c36 100644
--- a/src/soc/intel/xeon_sp/uncore.c
+++ b/src/soc/intel/xeon_sp/uncore.c
@@ -192,7 +192,7 @@
 	struct range_entry fsp_mem;
 
 	/* Only add dram resources once. */
-	if (dev->bus->secondary != 0)
+	if (dev->bus->secondary != 0 || dev->bus->segment_group != 0)
 		return;
 
 	/* Read in the MAP registers and report their values. */