nb/intel/sandybridge/raminit: Separate Sandybridge and Ivybridge

Add custom files for Sandybridge and IvyBridge functions.
Move only the minimal required functions into separate files.
Both files' functions are going to call raminit_common functions.
No functionality is changed.

Sandybridge code path tested on Lenovo T420.

Change-Id: I1b1dfbd0857b59d3ae4392b73c033ee7a5aed243
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/17605
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/northbridge/intel/sandybridge/Makefile.inc b/src/northbridge/intel/sandybridge/Makefile.inc
index cc0228b..a40fa15 100644
--- a/src/northbridge/intel/sandybridge/Makefile.inc
+++ b/src/northbridge/intel/sandybridge/Makefile.inc
@@ -27,6 +27,8 @@
 ifeq ($(CONFIG_USE_NATIVE_RAMINIT),y)
 romstage-y += raminit.c
 romstage-y += raminit_common.c
+romstage-y += raminit_sandy.c
+romstage-y += raminit_ivy.c
 romstage-y += ../../../device/dram/ddr3.c
 else
 romstage-y += raminit_mrc.c