ARM64: Kconfig: Ensure Kconfig option is selectable

The ARM64_DMA_USE_IOMMU option was not selectable from the menuconfig
gui since it was not listed under a menu. Fix this.

Change-Id: Ieabc85fde23da8b2a7e32326f6c5fe3f48bc8a72
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 820c23d2..0b50576 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -221,32 +221,6 @@
 config SMP
 	def_bool y
 
-config ARM64_DMA_USE_IOMMU
-	bool
-	select ARM_HAS_SG_CHAIN
-	select NEED_SG_DMA_LENGTH
-
-if ARM64_DMA_USE_IOMMU
-
-config ARM64_DMA_IOMMU_ALIGNMENT
-	int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers"
-	range 4 9
-	default 8
-	help
-	  DMA mapping framework by default aligns all buffers to the smallest
-	  PAGE_SIZE order which is greater than or equal to the requested buffer
-	  size. This works well for buffers up to a few hundreds kilobytes, but
-	  for larger buffers it just a waste of address space. Drivers which has
-	  relatively small addressing window (like 64Mib) might run out of
-	  virtual space with just a few allocations.
-
-	  With this parameter you can specify the maximum PAGE_SIZE order for
-	  DMA IOMMU buffers. Larger buffers will be aligned only to this
-	  specified order. The order is expressed as a power of two multiplied
-	  by the PAGE_SIZE.
-
-endif
-
 config SWIOTLB
 	def_bool y
 
@@ -688,6 +662,37 @@
 
 source "mm/Kconfig"
 
+config ARM64_DMA_USE_IOMMU
+	bool "ARM64 DMA iommu integration"
+	select ARM_HAS_SG_CHAIN
+	select NEED_SG_DMA_LENGTH
+	help
+	  Enable using iommu through the standard dma apis.
+	  dma_alloc_coherent() will allocate scatter-gather memory
+	  which is made virtually contiguous via iommu.
+	  Enable if system contains IOMMU hardware.
+
+if ARM64_DMA_USE_IOMMU
+
+config ARM64_DMA_IOMMU_ALIGNMENT
+	int "Maximum PAGE_SIZE order of alignment for DMA IOMMU buffers"
+	range 4 9
+	default 8
+	help
+	  DMA mapping framework by default aligns all buffers to the smallest
+	  PAGE_SIZE order which is greater than or equal to the requested buffer
+	  size. This works well for buffers up to a few hundreds kilobytes, but
+	  for larger buffers it just a waste of address space. Drivers which has
+	  relatively small addressing window (like 64Mib) might run out of
+	  virtual space with just a few allocations.
+
+	  With this parameter you can specify the maximum PAGE_SIZE order for
+	  DMA IOMMU buffers. Larger buffers will be aligned only to this
+	  specified order. The order is expressed as a power of two multiplied
+	  by the PAGE_SIZE.
+
+endif
+
 config SECCOMP
 	bool "Enable seccomp to safely compute untrusted bytecode"
 	---help---