In case we receive NACK on DATA we shouldn't be resetting the controller,
rather we should issue STOP command. This will terminate the current
transaction and -EIO is returned.

While at that handle the SMBus Quick Command properly.
We shouldn't be setting the XLP9XX_I2C_CMD_READ/WRITE for such
transactions.

Signed-off-by: George Cherian <george.cherian@cavium.com>
Reviewed-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>