firmware: Hold a reference for of_find_compatible_node()

In of_register_trusted_foundations(), we need to hold the reference
returned by of_find_compatible_node() and then use it to call
of_node_put() for refcount balance.
Signed-off-by: Liang He <windhl@126.com>
Link: https://lore.kernel.org/r/20220628021640.4015-1-windhl@126.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/firmware/trusted_foundations.h

@@ -71,12 +71,16 @@ static inline void register_trusted_foundations(
 
 static inline void of_register_trusted_foundations(void)
 {
+	struct device_node *np = of_find_compatible_node(NULL, NULL, "tlm,trusted-foundations");
+
+	if (!np)
+		return;
+	of_node_put(np);
 	/*
 	 * If we find the target should enable TF but does not support it,
 	 * fail as the system won't be able to do much anyway
 	 */
-	if (of_find_compatible_node(NULL, NULL, "tlm,trusted-foundations"))
-		register_trusted_foundations(NULL);
+	register_trusted_foundations(NULL);
 }
 
 static inline bool trusted_foundations_registered(void)