Patch from Kevin Hilman

This patch increase available DMA-consistent memory allocated by dma_coherent_alloc(). The default remains at 2M (defined in asm/memory.h) and each platform has the ability to override in asm/arch-foo/memory.h.
Signed-off-by: Kevin Hilman <kevin@hilman.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>