perf annotate: Fix multiple memory and file descriptor leaks

Store SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF in variable *ret*, instead
of returning in the middle of the function and leaking multiple
resources: prog_linfo, btf, s and bfdf.

Addresses-Coverity-ID: 1454832 ("Structurally dead code")
Fixes: 11aad897 ("perf annotate: Don't return -1 for error when doing BPF disassembly")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20191014171047.GA30850@embeddedorSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/annotate.c

@@ -1758,7 +1758,7 @@ static int symbol__disassemble_bpf(struct symbol *sym,
 	info_node = perf_env__find_bpf_prog_info(dso->bpf_prog.env,
 						 dso->bpf_prog.id);
 	if (!info_node) {
-		return SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
+		ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
 		goto out;
 	}
 	info_linear = info_node->info_linear;