Add arch/arm/cpu/armv7/Kconfig with non-secure and virt options, this is a
preparation patch for adding an env variable to choose between secure /
non-secure boot on non-secure boot capable systems, specifically this
prepares for adding CONFIG_ARMV7_BOOT_SEC_DEFAULT as a proper Kconfig option.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>