i2c-pnx: fix setting start/stop condition

The start/stop condtions are set in different places repetedly in the i2c-pnx
driver.  Beside in i2c_pnx_start and i2c_pnx_stop the start/stop bit are also
set during the transfer of a i2c message in the master_xmit/rcv calls. This is
wrong since we can't set the start/stop condition during the transaction of a
single message any way. As a matter of fact, the driver will sometimes set both
the start and the stop bits at one time. This can be easily reproduced by
sending a simple read request like e.g
struct i2c_msg msgs[] = {
{ addr, 0, 1, buf },
{ addr, I2C_M_RD, offset, buf }
};
While processing the first message the i2c_pnx_master_xmit will set both the
start_bit and the stop_bit, which will eventually confuse the slave.

Fixed by remove setting start/stop condition from the transmit routines.
Signed-off-by: NLuotao Fu <l.fu@pengutronix.de>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

drivers/i2c/busses/i2c-pnx.c

@@ -172,12 +172,6 @@ static int i2c_pnx_master_xmit(struct i2c_pnx_algo_data *alg_data)
 		/* We still have something to talk about... */
 		val = *alg_data->mif.buf++;
 
-		if (alg_data->mif.len == 1) {
-			val |= stop_bit;
-			if (!alg_data->last)
-				val |= start_bit;
-		}
-
 		alg_data->mif.len--;
 		iowrite32(val, I2C_REG_TX(alg_data));
 
@@ -251,11 +245,6 @@ static int i2c_pnx_master_rcv(struct i2c_pnx_algo_data *alg_data)
 			__func__);
 
 		if (alg_data->mif.len == 1) {
-			/* Last byte, do not acknowledge next rcv. */
-			val |= stop_bit;
-			if (!alg_data->last)
-				val |= start_bit;
-
 			/*
 			 * Enable interrupt RFDAIE (data in Rx fifo),
 			 * and disable DRMIE (need data for Tx)