ARM: 9351/1: fault: Add "cut here" line for prefetch aborts

The common pattern in arm is to emit a "8<--- cut here ---" line for
faults, but it was missing for do_PrefetchAbort(). Add it.

Cc: Wang Kefeng <wangkefeng.wang@huawei.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>