ARM: relax conditions required for enabling Contiguous Memory Allocator

Contiguous Memory Allocator requires only paging and MMU enabled not
particular CPU architectures, so there is no need for strict dependency
on CPU type. This enables to use CMA on some older ARM v5 systems which
also might need large contiguous blocks for the multimedia processing hw
modules.

Reported-by: Prabhakar Lad <prabhakar.lad@ti.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Prabhakar Lad <prabhakar.lad@ti.com>