bpftool: bpf_link_get_from_fd support for LSM programs in lskel

bpf_link_get_from_fd currently returns a NULL fd for LSM programs.
LSM programs are similar to tracing programs and can also use
skel_raw_tracepoint_open.
Signed-off-by: NKP Singh <kpsingh@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220509214905.3754984-1-kpsingh@kernel.org

tools/bpf/bpftool/gen.c

@@ -549,6 +549,7 @@ static void codegen_attach_detach(struct bpf_object *obj, const char *obj_name)
 			printf("\tint fd = skel_raw_tracepoint_open(\"%s\", prog_fd);\n", tp_name);
 			break;
 		case BPF_PROG_TYPE_TRACING:
+		case BPF_PROG_TYPE_LSM:
 			if (bpf_program__expected_attach_type(prog) == BPF_TRACE_ITER)
 				printf("\tint fd = skel_link_create(prog_fd, 0, BPF_TRACE_ITER);\n");
 			else