arm: add pdev_archdata for dma_mask

The dma_mask which tells if device is dma capable is not being set by
arm platform device so that set_dma_mask() results in return -EIO always.
Add dma_mask in the platform_device arch data to set it to dma_mask.

Change-Id: Ia0c4ade7731d792b2538f374fffd99f927a6db74
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>