cma: Call dma_contiguous_early_fixup after allocation

Commit 42e668f4 cma: Delay non-placed memblocks until after all allocations
delayed calling memblock_alloc until later but didn't move the
fixup. Make sure to call the fixup after allocation of the
memblock.

Change-Id: I305c05f1b1e0b6aeb462746e91b30560ddf5b934
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>