wily: arm64: warning in numa_init() during booting

[Impact]
A kernel WARNING is printed on boot on arm64:

[ 0.000000] ------------[ cut here ]------------
[ 0.000000] WARNING: CPU: 0 PID: 0 at /build/linux-vmnY7Y/linux-4.2.0/arch/arm64/mm/numa.c:449 numa_init+0x90/0x398()
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.2.0-16-generic #19-Ubuntu
[ 0.000000] Hardware name: APM X-Gene Merlin board (DT)
[ 0.000000] Call trace:
[ 0.000000] [<ffffffc00008ab90>] dump_backtrace+0x0/0x178
[ 0.000000] [<ffffffc00008ad28>] show_stack+0x20/0x30
[ 0.000000] [<ffffffc0008a41d8>] dump_stack+0x7c/0x98
[ 0.000000] [<ffffffc0000bf9e8>] warn_slowpath_common+0xa0/0xe0
[ 0.000000] [<ffffffc0000bfbb0>] warn_slowpath_null+0x38/0x50
[ 0.000000] [<ffffffc000c3de84>] numa_init+0x8c/0x398
[ 0.000000] [<ffffffc000c3e1c0>] arm64_numa_init+0x30/0x40
[ 0.000000] [<ffffffc000c3ce20>] bootmem_init+0x74/0x12c
[ 0.000000] [<ffffffc000c3d5b0>] paging_init+0x198/0x224
[ 0.000000] [<ffffffc000c3a028>] setup_arch+0x284/0x624
[ 0.000000] [<ffffffc000c36718>] start_kernel+0xf0/0x424
[ 0.000000] ---[ end trace f24b6c88ae00fa9a ]---

Though it is believed to be innocuous, it isn't obviously so, and will likely scare users.

[Test Case]
Boot wily on an arm64 system and look for the above trace in dmesg.

[Regression Risk]
The NUMA patches for arm64 were merged in in preparation for a hardware enablement project that was later postponed. I'm very confident that there are no systems out there that can boot wily's kernel and benefit from these patches.