Add a generic register script handler

This is based on the RCBA configuration setup from haswell.
It handles PCI, BARs, IO, MMIO, and baytrail-specific IOSF.
I did not extend it to handle MSR yet but that would be another
potential register type.

There are a number of approaches to this kind of thing, but in the
end they have a lot of switch statements and a mass of #defines.
I'm not particularly set on any of the details so comments welcome.

BUG=chrome-os-partner:23635
BRANCH=rambi
TEST=emerge-rambi chromeos-coreboot-rambi

Change-Id: Ib873936ecf20fc996a8feeb72b9d04ddb523211f
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175206
Commit-Queue: Aaron Durbin <adurbin@chromium.org>
Tested-by: Aaron Durbin <adurbin@chromium.org>
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/4923
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/lib/Makefile.inc

@@ -110,6 +110,8 @@ ramstage-y += cbmem_info.c
 ramstage-y += hexdump.c
 romstage-y += hexdump.c
 
+ramstage-$(CONFIG_REG_SCRIPT) += reg_script.c
+
 romstage-$(CONFIG_CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM) += ramstage_cache.c
 
 ifneq ($(CONFIG_HAVE_ARCH_MEMSET),y)