tc35815: Fix an usage of streaming DMA API.

The tc35815 driver lacks a call to pci_dma_sync_single_for_device() on
receiving.  Recent fix of MIPS dma_sync_single_for_cpu() reveal this
bug.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>