ARM: 8427/1: dma-mapping: add support for offset parameter in dma_mmap()

IOMMU-based dma_mmap() implementation lacked proper support for offset
parameter used in mmap call (it always assumed that mapping starts from
offset zero). This patch adds support for offset parameter to IOMMU-based
implementation.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: stable@vger.kernel.org  # v3.6+
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/dma-mapping.c

@@ -1418,6 +1418,8 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 	if (off >= nr_pages || (usize >> PAGE_SHIFT) > nr_pages - off)
 		return -ENXIO;
 
+	pages += off;
+
 	do {
 		int ret = vm_insert_page(vma, uaddr, *pages++);
 		if (ret) {