The Cortex-M related Kconfig menus and options no longer show up at the top
level when "make ARCH=arm menuconfig" is issued. They show up under the
"General Platform Configuration" menu.
Change-Id: I6bf012e628212340f5e089d0193a9a71d90c79b9
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>