tools, bpftool: Fix memory leak in codegen error cases

Free the memory allocated for the template on error paths in function
codegen.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200610130804.21423-1-tklauser@distanz.ch

tools/bpf/bpftool/gen.c

@@ -224,6 +224,7 @@ static int codegen(const char *template, ...)
 		} else {
 			p_err("unrecognized character at pos %td in template '%s'",
 			      src - template - 1, template);
+			free(s);
 			return -EINVAL;
 		}
 	}
@@ -234,6 +235,7 @@ static int codegen(const char *template, ...)
 			if (*src != '\t') {
 				p_err("not enough tabs at pos %td in template '%s'",
 				      src - template - 1, template);
+				free(s);
 				return -EINVAL;
 			}
 		}