LINT: add KDTRACE_MIB_SDT to catch inconsistencies with struct tcpstat

Why only arm64? We want LINT coverage for kernels with DTrace and
without. Global NOTES doesn't have KDTRACE_HOOKS, but most machine
dependent NOTES have it. Except the x86 NOTES, which intentionally
doesn't have KDTRACE_HOOKS, so that there is coverage for a kernel without
DTrace. So lets use arm64, our second Tier 1 platform, to have a LINT
with maximum DTrace features enabled.

See also: daad0b6501359, 2f915345634e