sh: intc: Replace simple_strtoul() with kstrtoul()

The function simple_strtoul() performs no error checking
in scenarios where the input value overflows the intended
output variable.

We can replace the use of simple_strtoul() with the safer
alternative kstrtoul(). This also allows us to print an
error message in case of failure.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

drivers/sh/intc/userimask.c

@@ -32,8 +32,11 @@ store_intc_userimask(struct device *dev,
 		     const char *buf, size_t count)
 {
 	unsigned long level;
+	int ret;
 
-	level = simple_strtoul(buf, NULL, 10);
+	ret = kstrtoul(buf, 10, &level);
+	if (ret != 0)
+		return ret;
 
 	/*
 	 * Minimal acceptable IRQ levels are in the 2 - 16 range, but