staging/rts_pstor: remove braces {} in sd.c (sd_sdr_tuning_tx_cmd)

fixed below checkpatch warnings.
-WARNING: braces {} are not necessary for single statement blocks
Signed-off-by: Toshiaki Yamane <yamanetoshi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rts_pstor/sd.c

@@ -1496,9 +1496,8 @@ static int sd_sdr_tuning_tx_cmd(struct rtsx_chip *chip, u8 sample_point)
 	int retval;
 
 	retval = sd_change_phase(chip, sample_point, TUNE_TX);
-	if (retval != STATUS_SUCCESS) {
+	if (retval != STATUS_SUCCESS)
 		TRACE_RET(chip, STATUS_FAIL);
-	}
 
 	RTSX_WRITE_REG(chip, SD_CFG3, SD_RSP_80CLK_TIMEOUT_EN, SD_RSP_80CLK_TIMEOUT_EN);