i2c: Consistently reject unsupported transactions

Many PC SMBus host controller drivers don't properly handle the case
where they are requested to achieve a transaction they do not support.
Update them so that the consistently print a warning message and
return a single error value in this case.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 77aaa5f..2bde475 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -307,9 +307,6 @@
 	int status;
 
 	switch (size) {
-	case I2C_SMBUS_PROC_CALL:
-		dev_err(&adap->dev, "I2C_SMBUS_PROC_CALL not supported!\n");
-		return -EOPNOTSUPP;
 	case I2C_SMBUS_QUICK:
 		outb_p((addr << 1) | read_write,
 		       SMBHSTADD);
@@ -355,6 +352,9 @@
 		}
 		size = PIIX4_BLOCK_DATA;
 		break;
+	default:
+		dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
+		return -EOPNOTSUPP;
 	}
 
 	outb_p((size & 0x1C) + (ENABLE_INT9 & 1), SMBHSTCNT);