i2c: pnx: remove superfluous assignment

smatch rightfully says:

drivers/i2c/busses/i2c-pnx.c:499 i2c_pnx_xfer warn: unused return: stat = ioread32()
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-pnx.c

@@ -496,7 +496,7 @@ i2c_pnx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 	struct i2c_msg *pmsg;
 	int rc = 0, completed = 0, i;
 	struct i2c_pnx_algo_data *alg_data = adap->algo_data;
-	u32 stat = ioread32(I2C_REG_STS(alg_data));
+	u32 stat;
 
 	dev_dbg(&alg_data->adapter.dev,
 		"%s(): entering: %d messages, stat = %04x.\n",