bpf: Remove unneeded memset in queue_stack_map creation

__GFP_ZERO will clear the memory, so we don't need to memset it.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20220810151840.16394-2-laoar.shao@gmail.com


Signed-off-by: Alexei Starovoitov <ast@kernel.org>