ARM: 8437/1: dma-mapping: fix build warning with new DMA_ERROR_CODE definition

Commit 96231b26: ("ARM: 8419/1: dma-mapping: harmonize definition
of DMA_ERROR_CODE") changed the definition of DMA_ERROR_CODE to use
dma_addr_t, which makes the compiler barf on assigning this to an
"int" variable on ARM with LPAE enabled:
*************
In file included from /src/linux/include/linux/dma-mapping.h:86:0,
                 from /src/linux/arch/arm/mm/dma-mapping.c:21:
/src/linux/arch/arm/mm/dma-mapping.c: In function '__iommu_create_mapping':
/src/linux/arch/arm/include/asm/dma-mapping.h:16:24: warning:
overflow in implicit constant conversion [-Woverflow]
 #define DMA_ERROR_CODE (~(dma_addr_t)0x0)
                        ^
/src/linux/arch/arm/mm/dma-mapping.c:1252:15: note: in expansion of
macro DMA_ERROR_CODE'
  int i, ret = DMA_ERROR_CODE;
               ^
*************

Remove the actually unneeded initialization of "ret" in
__iommu_create_mapping() and move the variable declaration inside the
for-loop to make the scope of this variable more clear.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/dma-mapping.c

@@ -1257,7 +1257,7 @@ __iommu_create_mapping(struct device *dev, struct page **pages, size_t size)
 	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	dma_addr_t dma_addr, iova;
-	int i, ret = DMA_ERROR_CODE;
+	int i;
 
 	dma_addr = __alloc_iova(mapping, size);
 	if (dma_addr == DMA_ERROR_CODE)
@@ -1265,6 +1265,8 @@ __iommu_create_mapping(struct device *dev, struct page **pages, size_t size)
 
 	iova = dma_addr;
 	for (i = 0; i < count; ) {
+		int ret;
+
 		unsigned int next_pfn = page_to_pfn(pages[i]) + 1;
 		phys_addr_t phys = page_to_phys(pages[i]);
 		unsigned int len, j;