libbpf: Fix the incorrect reference to the memlock_rlim variable in the comment.

The variable "memlock_rlim_max" referenced in the comment does not exist.
I think that the author probably meant the variable "memlock_rlim". So,
correct it.

Signed-off-by: Jianyun Gao <jianyungao89@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251027032008.738944-1-jianyungao89@gmail.com

Author: Jianyun Gao

tools/lib/bpf/bpf.c

@@ -154,7 +154,7 @@ int bump_rlimit_memlock(void)
 
 	memlock_bumped = true;
 
-	/* zero memlock_rlim_max disables auto-bumping RLIMIT_MEMLOCK */
+	/* zero memlock_rlim disables auto-bumping RLIMIT_MEMLOCK */
 	if (memlock_rlim == 0)
 		return 0;