ARM: remove CPU_CP15 conditional from alignment.c

alignment.c will not be built unless CPU_CP15 is set:

config CPU_CP15
        bool

config CPU_CP15_MMU
        bool
        select CPU_CP15

config ALIGNMENT_TRAP
        bool
        depends on CPU_CP15_MMU

So there's no point having conditionals on CPU_CP15 within this code.

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