Fix unused-but-set-variable build breakage clang migrate to r433403

Bug: 199698959
Change-Id: I48d31cb28f2b150be8330d64f78baf99114a98fc
Signed-off-by: Alex Hong <rurumihong@google.com>
diff --git a/hall_sensor.c b/hall_sensor.c
index ef717b1..f16ce23 100644
--- a/hall_sensor.c
+++ b/hall_sensor.c
@@ -168,9 +168,8 @@
 	const char *buf, size_t count) {
 	struct hall_sensor_drv_data *hall_data = dev_get_drvdata(dev);
 	int val;
-	int result;
 
-	result = kstrtoint(buf, 10, &val);
+	kstrtoint(buf, 10, &val);
 
 	hall_sensor_enable(hall_data, !!val);