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
1 file changed