locking/lockdep: Cure noinstr fail

When the compiler doesn't feel like inlining, it causes a noinstr
fail:

  vmlinux.o: warning: objtool: lock_is_held_type()+0xb: call to lockdep_enabled() leaves .noinstr.text section

Fixes: 4d004099 ("lockdep: Fix lockdep recursion")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210106144017.592595176@infradead.org

kernel/locking/lockdep.c

@@ -79,7 +79,7 @@ module_param(lock_stat, int, 0644);
 DEFINE_PER_CPU(unsigned int, lockdep_recursion);
 EXPORT_PER_CPU_SYMBOL_GPL(lockdep_recursion);
 
-static inline bool lockdep_enabled(void)
+static __always_inline bool lockdep_enabled(void)
 {
 	if (!debug_locks)
 		return false;