ENGR00274412-1 dma: pxp: Port ePxP driver to 3.10

ENGR00274412-1 dma: pxp: Port ePxP driver to 3.10

It's ported from v3.5.7, which contains ePxP DMAENGINE driver and
a client driver named pxp_device. This patch also includes the changes:
- use uapi header file
- remove VM_RESERVED since it's deprecated, and drop redundant VM_IO flag
  since it's automatically set in remap_pfn_range()
- use <linux/platform_data/dma-imx.h> instead of <mach/dma.h>
- use devm_kzalloc() instead in pxp_probe()
- use macro __KERNEL__ in pxp_dma uapi header to avoid definition conflict

Signed-off-by: Robby Cai <R63905@freescale.com>