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

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

@@ -1872,26 +1872,22 @@ static int mmc_ddr_tuning(struct rtsx_chip *chip)
 
 	if (!(chip->sd_ctl & MMC_DDR_TX_PHASE_SET_BY_USER)) {
 		retval = sd_ddr_pre_tuning_tx(chip);
-		if (retval != STATUS_SUCCESS) {
+		if (retval != STATUS_SUCCESS)
 			TRACE_RET(chip, STATUS_FAIL);
-		}
 	} else {
 		retval = sd_change_phase(chip, (u8)chip->mmc_ddr_tx_phase, TUNE_TX);
-		if (retval != STATUS_SUCCESS) {
+		if (retval != STATUS_SUCCESS)
 			TRACE_RET(chip, STATUS_FAIL);
-		}
 	}
 
 	retval = sd_tuning_rx(chip);
-	if (retval != STATUS_SUCCESS) {
+	if (retval != STATUS_SUCCESS)
 		TRACE_RET(chip, STATUS_FAIL);
-	}
 
 	if (!(chip->sd_ctl & MMC_DDR_TX_PHASE_SET_BY_USER)) {
 		retval = sd_tuning_tx(chip);
-		if (retval != STATUS_SUCCESS) {
+		if (retval != STATUS_SUCCESS)
 			TRACE_RET(chip, STATUS_FAIL);
-		}
 	}
 
 	return STATUS_SUCCESS;