[PATCH] ARM SMP: convert alignment enable

The current vector entry system does not allow for SMP.  In
order to work around this, we need to eliminate our reliance
on the fixed save areas, which breaks the way we enable
alignment traps.  This patch makes the alignment trap enable
code independent of the way we handle the save areas.

Signed-off-by: Russell King <rmk@arm.linux.org.uk>