i2c: sh_mobile: define start_ch() void as it only returns 0 anyhow

After various refactoring over the years, start_ch() doesn't return
errno anymore, so make the function return void. This saves the error
handling when calling it which in turn eases cleanup of resources of a
future patch.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-sh_mobile.c

@@ -602,7 +602,7 @@ static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
 	dma_async_issue_pending(chan);
 }
 
-static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
+static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
 		     bool do_init)
 {
 	if (do_init) {
@@ -627,7 +627,6 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
 
 	/* Enable all interrupts to begin with */
 	iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
-	return 0;
 }
 
 static int poll_dte(struct sh_mobile_i2c_data *pd)
@@ -698,9 +697,7 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
 		pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
 		pd->stop_after_dma = false;
 
-		err = start_ch(pd, msg, do_start);
-		if (err)
-			break;
+		start_ch(pd, msg, do_start);
 
 		if (do_start)
 			i2c_op(pd, OP_START, 0);