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

commit 7e31210349e9e03a9a4dff31ab5f2bc83e8e84f5 upstream.

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>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>