powerpc/ps3: Fix hcall lv1_net_stop_rx_dma

The lv1_net_stop_tx_dma and net_stop_rx_dma hcalls take 2, not 3 input
arguments.  Adjust the lv1 hcall table and all calls.

Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>