staging: android: ion: Fix dma direction for dma_sync_sg_for_cpu/device

Use the direction argument passed into begin_cpu_access
and end_cpu_access when calling the dma_sync_sg_for_cpu/device.
The actual cache primitive called depends on the direction
passed in.

Signed-off-by: Sushmita Susheelendra <ssusheel@codeaurora.org>
Cc: stable <stable@vger.kernel.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>