sandy/ivy native: dedup romstage.c main()

Change-Id: I9909a5b2bdb4b59219db6304fa4332802fe0301c
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7127
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
diff --git a/src/mainboard/lenovo/t520/Makefile.inc b/src/mainboard/lenovo/t520/Makefile.inc
index d514d4b..265059a 100644
--- a/src/mainboard/lenovo/t520/Makefile.inc
+++ b/src/mainboard/lenovo/t520/Makefile.inc
@@ -18,3 +18,4 @@
 ##
 
 smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c
+romstage-y += gpio.c