When v6 and >=v7 boards are supported in the same kernel, the
__und_usr code currently makes a build-time assumption that Thumb-2
instructions occurring in userspace don't need to be supported.
Strictly speaking this is incorrect.

This patch fixes the above case by doing a run-time check on the
CPU architecture in these cases.  This only affects kernels which
support v6 and >=v7 CPUs together: plain v6 and plain v7 kernels
are unaffected.
Signed-off-by: NDave Martin <dave.martin@linaro.org>
Reviewed-by: NJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>