Ignoring the return value from a call to the kernel dma_map API functions
can cause data corruption and system instability.  Check the return value
and take appropriate action.
Signed-off-by: NGreg Rose <gregory.v.rose@intel.com>
Tested-by: NSibai Li <sibai.li@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>