i2c: mxs: fix error message in pio transfer

If I2C_M_RD flag is set SELECT command is sent and afterward READ
command. The patch fixes READ command to return READ failure error
message instead of SELECT failure error message.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>