samples/bpf: fix trace_output example

llvm cannot always recognize memset as builtin function and optimize
it away, so just delete it. It was a leftover from testing
of bpf_perf_event_output() with large data structures.

Fixes: 39111695 ("samples: bpf: add bpf_perf_event_output example")
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

samples/bpf/trace_output_kern.c

@@ -18,7 +18,6 @@ int bpf_prog1(struct pt_regs *ctx)
 		u64 cookie;
 	} data;
 
-	memset(&data, 0, sizeof(data));
 	data.pid = bpf_get_current_pid_tgid();
 	data.cookie = 0x12345678;