mmc: debugfs: correct wrong voltage value

Correct the wrong voltage value shown in debugfs for mmc/sd/sdio.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Fixes: 42cd95a0603e ("mmc: core: debugfs: Add signal_voltage to ios dump")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 154aced..65cc0ac 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -170,7 +170,7 @@
 		str = "invalid";
 		break;
 	}
-	seq_printf(s, "signal voltage:\t%u (%s)\n", ios->chip_select, str);
+	seq_printf(s, "signal voltage:\t%u (%s)\n", ios->signal_voltage, str);
 
 	switch (ios->drv_type) {
 	case MMC_SET_DRIVER_TYPE_A: