i2o: core: added two flag definitions.

Added:
	* I2O_FLAG_RAW_RX
	* I2O_FLAG_RAW_TX

These flags are supposed to be used in the i2o_dev_xfer function (the
flags argument). When you set either of them, the respective operation
will be carried out as a direct operation whenever possible. If its not
possible, the bit will be truncated and a buffered operation will be
done.

Signed-off-by: Michel Megens <dev@michelmegens.net>