ARM: l2c: add L2C-210 specific handlers

Add L2C-210 specific cache operation handlers.  These are tailored to
the requirements of the L2C-210 cache controller, which doesn't
require any workarounds.  We avoid using the way operations during
normal operation, which means we can avoid locking: the only time
we use the way operations are during initialisation, and when
disabling the cache.

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