drivers/mrc_cache: move mrc_cache support to drivers

There's nothing intel-specific about the current mrc_cache support.
It's logic manages saving non-volatile areas into the boot media.
Therefore, expose it to the rest of the system for any and all to
use.

BUG=b:69614064

Change-Id: I3b331c82a102f88912a3e10507a70207fb20aecc
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/22901
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/drivers/mrc_cache/Makefile.inc

@@ -0,0 +1,16 @@
+
+romstage-$(CONFIG_CACHE_MRC_SETTINGS) += mrc_cache.c
+ramstage-$(CONFIG_CACHE_MRC_SETTINGS) += mrc_cache.c
+
+# Create and add the MRC cache to the cbfs image
+ifneq ($(CONFIG_CHROMEOS),y)
+$(obj)/mrc.cache: $(obj)/config.h
+	dd if=/dev/zero count=1 \
+	bs=$(shell printf "%d" $(CONFIG_MRC_SETTINGS_CACHE_SIZE) ) | \
+	tr '\000' '\377' > $@
+
+cbfs-files-$(CONFIG_CACHE_MRC_SETTINGS) += mrc.cache
+mrc.cache-file := $(obj)/mrc.cache
+mrc.cache-position := $(CONFIG_MRC_SETTINGS_CACHE_BASE)
+mrc.cache-type := mrc_cache
+endif