i2c-pca-algo: Fix error code

Give a more concrete error code, when the bus is not idle.

Signed-off-by: Wolfram Sang <[e-mail]>
Signed-off-by: Jean Delvare <[e-mail]>

drivers/i2c/algos/i2c-algo-pca.c

···
 	}
 	if (state != 0xf8) {
 		dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
-		return -EIO;
+		return -EAGAIN;
 	}
 
 	DEB1("{{{ XFER %d messages\n", num);