mmc_test: change simple_strtol() to strict_strtol()

It's better to use strict_strtol() to convert user's input and strictly
check it. At least it forbids to interpret wrong input as a 0 and
prevents to run all tests.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/card/mmc_test.c

@@ -2024,9 +2024,10 @@ static ssize_t mmc_test_store(struct device *dev,
 {
 	struct mmc_card *card = mmc_dev_to_card(dev);
 	struct mmc_test_card *test;
-	int testcase;
+	long testcase;
 
-	testcase = simple_strtol(buf, NULL, 10);
+	if (strict_strtol(buf, 10, &testcase))
+		return -EINVAL;
 
 	test = kzalloc(sizeof(struct mmc_test_card), GFP_KERNEL);
 	if (!test)