Add sysctl to track the resource consumption of ACPI interrupts.

Submitted by:	gibbs
MFC after:	1 month
Sponsored by:	Spectra Logic
MFSpectraBSD:	636827 on 2012/09/28
Remove lock init from radix.c.
Radix has never managed its locking itself.
The only consumer using radix with embeded rwlock
is system routing table. Move per-AF lock inits there.