rsi_91x: fix uninitialized variable

There is a potential execution path in which variable ret is returned
without being properly initialized previously.

Fix this by storing the value returned by function
rsi_usb_master_reg_write into _ret_.

Addresses-Coverity-ID: 1468407 ("Uninitialized scalar variable")
Fixes: 16d3bb7b2f37 ("rsi: disable fw watchdog timer during reset")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rsi/rsi_91x_usb.c

@@ -687,9 +687,10 @@ static int rsi_reset_card(struct rsi_hw *adapter)
 	 */
 	msleep(100);
 
-	if (rsi_usb_master_reg_write(adapter, SWBL_REGOUT,
-				     RSI_FW_WDT_DISABLE_REQ,
-				     RSI_COMMON_REG_SIZE) < 0) {
+	ret = rsi_usb_master_reg_write(adapter, SWBL_REGOUT,
+				       RSI_FW_WDT_DISABLE_REQ,
+				       RSI_COMMON_REG_SIZE);
+	if (ret < 0) {
 		rsi_dbg(ERR_ZONE, "Disabling firmware watchdog timer failed\n");
 		goto fail;
 	}