mwl8: fix build warning.

This patch fixes a build warning in mwl8.c.
(Marvell TOPDOG wireless driver)

The warning it fixes is: "large integer implicitly truncated to unsigned type."

The rx_ctrl member of the mwl8k_rx_desc struct is 8 bit (__u8 ), whereas trying
to assign it a 32 bit value (which is returned from  cpu_to_le32())
causes the compiler to issue
a truncation warning.
Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwl8k.c

@@ -893,8 +893,7 @@ static int mwl8k_rxq_init(struct ieee80211_hw *hw, int index)
 		rx_desc->next_rx_desc_phys_addr =
 			cpu_to_le32(rxq->rx_desc_dma
 						+ nexti * sizeof(*rx_desc));
-		rx_desc->rx_ctrl =
-			cpu_to_le32(MWL8K_RX_CTRL_OWNED_BY_HOST);
+		rx_desc->rx_ctrl = MWL8K_RX_CTRL_OWNED_BY_HOST;
 	}
 
 	return 0;