tracing: Initialize val to zero in parse_entry of inject code

gcc produces a variable may be uninitialized warning for "val" in
parse_entry(). This is really a false positive, but the code is subtle
enough to just initialize val to zero and it's not a fast path to worry
about it.

Marked for stable to remove the warning in the stable trees as well.

Cc: stable@vger.kernel.org
Fixes: 6c3edaf ("tracing: Introduce trace event injection")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_events_inject.c

@@ -195,7 +195,7 @@ static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
 	unsigned long irq_flags;
 	void *entry = NULL;
 	int entry_size;
-	u64 val;
+	u64 val = 0;
 	int len;
 
 	entry = trace_alloc_entry(call, &entry_size);