i2c-designware: i2c_dw_func: Set I2C_FUNC_SMBUS_foo bits

Set proper I2C_FUNC_SMBUS_* bits so that the driver could be used with
some utilities requiring SMBus functionalities, such as i2c-tools.

Note that DW I2C core doesn't support I2C_FUNC_SMBUS_QUICK, as it's not
capable of zero-length data transactions.

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

drivers/i2c/busses/i2c-designware.c

@@ -528,7 +528,12 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 
 static u32 i2c_dw_func(struct i2c_adapter *adap)
 {
-	return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR;
+	return	I2C_FUNC_I2C |
+		I2C_FUNC_10BIT_ADDR |
+		I2C_FUNC_SMBUS_BYTE |
+		I2C_FUNC_SMBUS_BYTE_DATA |
+		I2C_FUNC_SMBUS_WORD_DATA |
+		I2C_FUNC_SMBUS_I2C_BLOCK;
 }
 
 static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)