BACKPORT: ARM: update FIQ support for relocation of vectors

(cherry pick from commit e39e3f3e)

FIQ should no longer copy the FIQ code into the user visible vector
page.  Instead, it should use the hidden page.  This change makes
that happen.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Bug: 9674955
Bug: 25773781
Change-Id: I381c81a8e7840ae27e8b6d9900ba6d9144ed8781