[RFT] i2c: sh_mobile: avoid unnecessary register read

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

There is no data when the first WAIT interrupt arrives. No need to read
something then.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

I am not super happy with (real pos >= 0) done twice, but I didn't find a
better solution yet. The compiler will make this cheap anyhow, I guess.

Jacopo: can you please test this on top of all other patches?

 drivers/i2c/busses/i2c-sh_mobile.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 80561ffbcf7b46..40a66d466c3c49 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -433,8 +433,9 @@ static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
 				break;
 			}
 			data = i2c_op(pd, OP_RX_STOP_DATA, 0);
-		} else
+		} else if (real_pos >= 0) {
 			data = i2c_op(pd, OP_RX, 0);
+		}
 
 		if (real_pos >= 0)
 			pd->msg->buf[real_pos] = data;
-- 
2.11.0