o Provide function kvm_read_zpcpu() to access UMA_ZONE_PCPU allocations.
o Provide function kvm_counter_u64_fetch() to fetch valut of a counter(9).

Sponsored by:	Nginx, Inc.
Use kvm_counter_u64_fetch() to fix obtaining ipstat and tcpstat from
kernel core files.

Sponsored by:	Nginx, Inc.
Create controller-level DMA tag, handling range of supported addresses.
That simplifies logic for channels and gives the bus information about what
device actually allocated the tag.

Submitted by:	jhb@