extcon: sm5502: Fix bug to check cable type

This patch fix bug when checking cable type. SM5502 have to use ADC value
to get correct cable type.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/drivers/extcon/extcon-sm5502.c b/drivers/extcon/extcon-sm5502.c
index 560d7dc..a1ba924 100644
--- a/drivers/extcon/extcon-sm5502.c
+++ b/drivers/extcon/extcon-sm5502.c
@@ -300,7 +300,7 @@
 	 * If ADC is SM5502_MUIC_ADC_GROUND(0x0), external cable hasn't
 	 * connected with to MUIC device.
 	 */
-	cable_type &= SM5502_REG_ADC_MASK;
+	cable_type = adc & SM5502_REG_ADC_MASK;
 	if (cable_type == SM5502_MUIC_ADC_GROUND)
 		return SM5502_MUIC_ADC_GROUND;