Add dummy Kconfig options for armv7

This adds a dummy config for ARMV7 for developing various
follow-up patches which rely on ARCH_ARMV7.

Change-Id: Id913054d916f41607d10ebc02aaf74082e14b554
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/1939
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)

src/arch/armv7/Kconfig

@@ -0,0 +1,3 @@
+menu "Architecture (armv7)"
+
+endmenu