verstage: provide support for serial console

verstage previously lacked serial console support.
Add the necessary objects and macro checks to allow
verstage to include the serial console.

Change-Id: Ibe911ad347cac0b089f5bc0d4263956f44f3d116
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10196
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)

src/lib/Makefile.inc

@@ -141,11 +141,13 @@ romstage-y += version.c
 ramstage-y += version.c
 smm-y += version.c
 secmon-y += version.c
+verstage-y += version.c
 
 $(obj)/lib/version.bootblock.o : $(obj)/build.h
 $(obj)/lib/version.romstage.o : $(obj)/build.h
 $(obj)/lib/version.ramstage.o : $(obj)/build.h
 $(obj)/lib/version.smm.o : $(obj)/build.h
+$(obj)/lib/version.verstage.o : $(obj)/build.h
 
 romstage-y += bootmode.c
 ramstage-y += bootmode.c