lib: stackdepot: fix ignoring return value warning

Fix the below ignoring return value warning for kstrtobool in
is_stack_depot_disabled function.

lib/stackdepot.c: In function 'is_stack_depot_disabled':
lib/stackdepot.c:154:2: warning: ignoring return value of 'kstrtobool'
declared with attribute 'warn_unused_result' [-Wunused-result]

Link: https://lkml.kernel.org/r/[email protected]
Fixes: b9779ab ("lib: stackdepot: add support to disable stack depot")
Signed-off-by: Vijayanand Jitta <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Vijayanand Jitta

lib/stackdepot.c

@@ -151,8 +151,10 @@ static struct stack_record **stack_table;
 
 static int __init is_stack_depot_disabled(char *str)
 {
-	kstrtobool(str, &stack_depot_disable);
-	if (stack_depot_disable) {
+	int ret;
+
+	ret = kstrtobool(str, &stack_depot_disable);
+	if (!ret && stack_depot_disable) {
 		pr_info("Stack Depot is disabled\n");
 		stack_table = NULL;
 	}