sys/src/9k/k10: add ethervirtio10 in kernel configurations

sys/src/9k/386: import ethervirtio10 from 9front (thanks Cinap Lenrek)

sys/src/9k/k10: add sdvirtio10 in kernel configurations

sys/src/9k/386: import sdvirtio10 from 9front (thanks Cinap Lenrek)

sys/src/9k/386: implement custom PCI capabilities enumeration (thanks Cinap Lenrek)

sys/src/9k/386: implement PCI capabilities (thanks Erik Quanstrom)

sys/src/9k/k10: increase SEGMAPSIZE to 65536

sys/src/9k/k10: use physalloc in MMU (thanks The NIX Authors)

sys/src/9k/port: support multiple page sizes in page allocator

sys/src/9k/k10: fix linked list after physfree (thanks Remi Pommarel)

sys/src/9k/k10: handle 4 KB blocks in physalloc

sys/src/9k/k10: import physalloc from NIX (thanks The NIX Authors)

sys/src/9k/port: fix memory leak in qmalloc

sys/src/9k: add mmucachectl function (thanks Charles Forsyth)

sys/src/9k/port: add isdmaok function (thanks Charles Forsyth)

sys/src/9k/port: add iskaddr macro (thanks Charles Forsyth)

sys/src/9k/port: handle SG_CACHED (thanks Charles Forsyth)

sys/src/9k/port: copy lg2pgsize in dupseg

sys/src/9k/port: use page size instead of PGSZ constant in sysseg

sys/src/9k/port: use page size instead of PGSZ constant in sysproc (thanks Charles Forsyth)

sys/src/9k/port: replace 1<<ps->lg2pgsize by physsegpgsize(ps)

sys/src/9k/port: replace 1<<s->lg2pgsize by segpgsize(s)

sys/src/9k/port: replace 1<<p->lg2size by pagesize(p) (thanks Charles Forsyth)

sys/src/9k/k10: replace print by DBG

sys/src/9k/k10: remove braces around if