misc: fastrpc: add checked value for dma_set_mask

There be should check return value from dma_set_mask to throw some info
if fail to set dma mask.

Detected by CoverityScan, CID# 1443983:  Error handling issues (CHECKED_RETURN)

Fixes: f6f9279f ("misc: fastrpc: Add Qualcomm fastrpc basic driver model")
Signed-off-by: Bo YU <tsu.yubo@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>