mainboard/intel/galileo: Add GPIO initialization

Add Kconfig to configure coreboot for a specific Galileo board.
Configure the GPIOs for the specific Galileo board.

TEST=Build and run on Galileo Gen2

Change-Id: I992460d506b5543915c27f6a531da4b1a53d6505
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/14826
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/mainboard/intel/galileo/Makefile.inc b/src/mainboard/intel/galileo/Makefile.inc
index 3ffba1c..382f8b9 100644
--- a/src/mainboard/intel/galileo/Makefile.inc
+++ b/src/mainboard/intel/galileo/Makefile.inc
@@ -14,3 +14,5 @@
 ##
 
 CPPFLAGS_common += -I$(src)/vendorcode/intel/fsp/fsp1_1/quark
+
+romstage-y += gpio.c