Input: convert drivers to use strict_strtoul()

strict_strtoul() allows newline character at the end of the the input
string and therefore is more user-friendly.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index ce6f48c..efbbbe4 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -461,10 +461,11 @@
 				     const char *buf, size_t count)
 {
 	struct ads7846 *ts = dev_get_drvdata(dev);
-	char *endp;
-	int i;
+	long i;
 
-	i = simple_strtoul(buf, &endp, 10);
+	if (strict_strtoul(buf, 10, &i))
+		return -EINVAL;
+
 	spin_lock_irq(&ts->lock);
 
 	if (i)