bpf: fix integer overflow in queue_stack_map

Fix the following issues:

- allow queue_stack_map for root only
- fix u32 max_entries overflow
- disallow value_size == 0

Fixes: f1a2e44a

 ("bpf: add queue and stack maps")
Reported-by: Wei Wu <ww9210@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Mauricio Vasquez B <mauricio.vasquez@polito.it>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>