bpf: Fix bpf_ringbuf_output() signature to return long

Due to bpf tree fix merge, bpf_ringbuf_output() signature ended up with int as
a return type, while all other helpers got converted to returning long. So fix
it in bpf-next now.

Fixes: b0659d8a ("bpf: Fix definition of bpf_ringbuf_output() helper in UAPI comments")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200727224715.652037-1-andriin@fb.com

include/uapi/linux/bpf.h

@@ -3241,7 +3241,7 @@ union bpf_attr {
  *	Return
  *		The id is returned or 0 in case the id could not be retrieved.
  *
- * int bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
+ * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
  * 	Description
  * 		Copy *size* bytes from *data* into a ring buffer *ringbuf*.
  * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification

tools/include/uapi/linux/bpf.h

@@ -3241,7 +3241,7 @@ union bpf_attr {
  *	Return
  *		The id is returned or 0 in case the id could not be retrieved.
  *
- * int bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
+ * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
  * 	Description
  * 		Copy *size* bytes from *data* into a ring buffer *ringbuf*.
  * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification