mb/amd/birman/update_devicetree_phoenix_opensil: use common header file

Instead of including stub/mpio/chip.h, include chip/mpio/chip.h that
will include the correct implementation to be able to use the same file
with both the openSIL stub and the actual openSIL implementation glue
code.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Iaae26a0dfe0ba96842e72582c06f1b0b3f29871c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82472
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/amd/birman/update_devicetree_phoenix_opensil.c

@@ -2,7 +2,7 @@
 
 #include <device/device.h>
 #include <soc/soc_util.h>
-#include <vendorcode/amd/opensil/stub/mpio/chip.h>
+#include <vendorcode/amd/opensil/chip/mpio/chip.h>
 #include "update_devicetree.h"
 
 static void mainboard_update_mpio(void)