firmware_loader: Replace simple_strtol() with kstrtoint()

Replace deprecated simple_strtol() calls with kstrtoint() in
timeout_store() and firmware_loading_store() functions to
improve input validation and error handling. The simple_strtol()
function does not provide proper error checking for invalid input,
while kstrtoint() returns an error for malformed strings.

This change adds proper validation for user input from sysfs attributes,
returning -EINVAL for invalid numeric strings instead of silently accepting
potentially malformed input. The behavior for valid numeric input remains
unchanged.

The simple_strtol() function is deprecated in favor of kstrtoint() family
functions which provide better error handling and are recommended for new
code and replacements.

Signed-off-by: Kaushlendra Kumar <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/base/firmware_loader/sysfs.c

···
 static ssize_t timeout_store(const struct class *class, const struct class_attribute *attr,
 			     const char *buf, size_t count)
 {
-	int tmp_loading_timeout = simple_strtol(buf, NULL, 10);
+	int tmp_loading_timeout;
+
+	if (kstrtoint(buf, 10, &tmp_loading_timeout))
+		return -EINVAL;
 
 	if (tmp_loading_timeout < 0)
 		tmp_loading_timeout = 0;
···
 	struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
 	struct fw_priv *fw_priv;
 	ssize_t written = count;
-	int loading = simple_strtol(buf, NULL, 10);
+	int loading;
+
+	if (kstrtoint(buf, 10, &loading))
+		return -EINVAL;
 
 	mutex_lock(&fw_lock);
 	fw_priv = fw_sysfs->fw_priv;