bcma: invalidate the mapped core over suspend/resume

This clears the currently mapped core when suspending, to force
re-mapping after resume. Without that we were touching default core
registers believing some other core is mapped. Such a behaviour
resulted in lockups on some machines.

Cc: stable@vger.kernel.org
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>