mm/cma: Move dma contiguous changes into a seperate config

We want to use CMA for allocating hash page table and real mode area for
PPC64. Hence move DMA contiguous related changes into a seperate config
so that ppc64 can enable CMA without requiring DMA contiguous.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[removed defconfig changes]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index 01b5c84..00141d3 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -57,7 +57,7 @@
 struct page;
 struct device;
 
-#ifdef CONFIG_CMA
+#ifdef CONFIG_DMA_CMA
 
 /*
  * There is always at least global CMA area and a few optional device