ARM: provide common method to clear bits in CPU control register

Several places open-code this manipulation, let's consolidate this.

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

diff --cc arch/arm/mm/alignment.c
Simple merge

diff --cc arch/arm/mm/init.c
Simple merge

diff --cc arch/arm/mm/mm.h
Simple merge

diff --cc arch/arm/mm/mmu.c
Simple merge