msm: camera: sensor: Request allocating DMA-able memory from DMA zone

When DMA I/O is performed to or from high memory, an area is allocated
in low memory known as a bounce buffer. When data travels between a
device and high memory, it is first copied through the bounce buffer.
Systems with a large amount of high memory and intense I/O activity
can create a large number of bounce buffers that can cause memory
shortage problems.
In general, when communicating to SPI framework,it's recommended to
use gfp_dma,since the buffer mm client passes is used by the spi
driver for dma ops.

CRs-Fixed: 967770
Change-Id: Idd7e0229d1a128516298ee18bf2c798e6218c71b
Signed-off-by: Azam Sadiq Pasha Kapatrala Syed <akapatra@codeaurora.org>