no need for vmap::lock anymore either

than modifying the vma's type and vmnode inplace.

about what fields can/cannot be changed by another core
while the object is allocated.

minor fix up: mv hwvm.hh include/hwvm.hh

Conflicts:
	qlock.h

more flexible updatepages() interface
PTE locking (using one of the free PTE bits)
guard against concurrent unmaps (except no way to check if vma is deleted yet..)

CPU may have interrupts disabled waiting for that spinlock too, and
will never acknowledge our tlb flush..

read the next pointer, and then unlock a node.  otherwise, the next pointer
changes and we try to unlock subsequent nodes that we never locked.