media: omap3isp: Don't use GFP_DMA

The isp stat driver allocates memory for DMA and uses GFP_DMA flag for
dev_alloc_coherent. The flag is no longer needed as the DMA mask is used
for the purpose. Remove it.

Reported-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>