tracing: Fix typo from "static inlin" to "static inline"

The trace.h header when called without CONFIG_EVENT_TRACING enabled
(seldom done), will not compile because of a typo in the protocol
of trace_event_enum_update().

Cc: stable@vger.kernel.org # 4.1+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.h

@@ -1312,7 +1312,7 @@ void trace_event_init(void);
 void trace_event_enum_update(struct trace_enum_map **map, int len);
 #else
 static inline void __init trace_event_init(void) { }
-static inlin void trace_event_enum_update(struct trace_enum_map **map, int len) { }
+static inline void trace_event_enum_update(struct trace_enum_map **map, int len) { }
 #endif
 
 extern struct trace_iterator *tracepoint_print_iter;