bpf: Switch BPF_F_KPROBE_MULTI_RETURN macro to enum

Switching BPF_F_KPROBE_MULTI_RETURN macro to anonymous enum,
so it'd show up in vmlinux.h. There's not functional change
compared to having this as macro.
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-2-jolsa@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

include/uapi/linux/bpf.h

@@ -1186,7 +1186,9 @@ enum bpf_perf_event_type {
 /* link_create.kprobe_multi.flags used in LINK_CREATE command for
  * BPF_TRACE_KPROBE_MULTI attach type to create return probe.
  */
-#define BPF_F_KPROBE_MULTI_RETURN	(1U << 0)
+enum {
+	BPF_F_KPROBE_MULTI_RETURN = (1U << 0)
+};
 
 /* link_create.netfilter.flags used in LINK_CREATE command for
  * BPF_PROG_TYPE_NETFILTER to enable IP packet defragmentation.

tools/include/uapi/linux/bpf.h

@@ -1186,7 +1186,9 @@ enum bpf_perf_event_type {
 /* link_create.kprobe_multi.flags used in LINK_CREATE command for
  * BPF_TRACE_KPROBE_MULTI attach type to create return probe.
  */
-#define BPF_F_KPROBE_MULTI_RETURN	(1U << 0)
+enum {
+	BPF_F_KPROBE_MULTI_RETURN = (1U << 0)
+};
 
 /* link_create.netfilter.flags used in LINK_CREATE command for
  * BPF_PROG_TYPE_NETFILTER to enable IP packet defragmentation.