nb/intel/sandybridge/peg: Add PEG driver stub

Required for other ACPI generators, like the one used for _ROM.

* Add ACPI code for PEG10/PEG11/PEG12/PEG60 and include it on all platforms.
* Add PCIe driver for PEG. The driver returns ACPI names for ssdt generators.

Needs test on real hardware.

Change-Id: I96835c43522580c95fd4f250c56bf9438e993bc1
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/22337
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/northbridge/intel/sandybridge/Makefile.inc b/src/northbridge/intel/sandybridge/Makefile.inc
index 1470353..d08b141 100644
--- a/src/northbridge/intel/sandybridge/Makefile.inc
+++ b/src/northbridge/intel/sandybridge/Makefile.inc
@@ -17,6 +17,7 @@
 
 ramstage-y += ram_calc.c
 ramstage-y += northbridge.c
+ramstage-y += pcie.c
 ramstage-y += gma.c
 ramstage-$(CONFIG_SANDYBRIDGE_IVYBRIDGE_LVDS) += gma_sandybridge_lvds.c
 ramstage-$(CONFIG_SANDYBRIDGE_IVYBRIDGE_LVDS) += gma_ivybridge_lvds.c