extcon: Use BIT() macro for the left-shift operation

This patch just uses the BIT() macro to make the code simple.
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/extcon/extcon.c

@@ -377,7 +377,7 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 	for (i = 0; i < edev->max_supported; i++) {
 		count += sprintf(buf + count, "%s=%d\n",
 				extcon_info[edev->supported_cable[i]].name,
-				 !!(edev->state & (1 << i)));
+				 !!(edev->state & BIT(i)));
 	}
 
 	return count;