libbpf: fix potential overflow in ring__consume_n()

ringbuf_process_ring() return int64_t, while ring__consume_n() assigns
it to int. It's highly unlikely, but possible for ringbuf_process_ring()
to return value larger than INT_MAX, so use int64_t. ring__consume_n()
does check INT_MAX before returning int result to the user.

Fixes: 4d22ea94 ("libbpf: Add ring__consume_n / ring_buffer__consume_n")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240430201952.888293-1-andrii@kernel.orgSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

tools/lib/bpf/ringbuf.c

@@ -405,7 +405,7 @@ int ring__map_fd(const struct ring *r)
 
 int ring__consume_n(struct ring *r, size_t n)
 {
-	int res;
+	int64_t res;
 
 	res = ringbuf_process_ring(r, n);
 	if (res < 0)