baytrail: allow SD card controller capabilities overrides

The SD card controller can have the capabilities it supports
to be overridden. Add two optional fields to the chip structure
to allow the mainboard to override the SD card controller
capabilities.

BUG=chrome-os-partner:24423
BRANCH=None
TEST=Built and booted. Noted capabilities override console output.

Change-Id: Ibfef8f765b35eeec6da969dd05f5484f8672a7b9
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/179414
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/4997
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins)
diff --git a/src/soc/intel/baytrail/Makefile.inc b/src/soc/intel/baytrail/Makefile.inc
index 6485cc0..48fb4b4 100644
--- a/src/soc/intel/baytrail/Makefile.inc
+++ b/src/soc/intel/baytrail/Makefile.inc
@@ -43,6 +43,7 @@
 ramstage-y += emmc.c
 ramstage-y += lpss.c
 ramstage-y += pcie.c
+ramstage-y += sd.c
 
 # Remove as ramstage gets fleshed out
 ramstage-y += placeholders.c