ARM: l2x0: Optimise the range based operations

For the big buffers which are in excess of cache size, the maintaince
operations by PA are very slow. For such buffers the maintainace
operations can be speeded up by using the WAY based method.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>