ARM: 6186/1: Avoid the CONSISTENT_DMA_SIZE warning on noMMU builds

This macro is not defined when !CONFIG_MMU so this patch moves the
CONSISTENT_* definitions to the CONFIG_MMU section.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>