kernel/i386: Implement pmap_invalidate_cache_pages()
test/vkernel - Allow using HAMMER filesystem as vkernel root.
disklabel64 - Increased verification of the partition format.

* Check whether the filesystem type is specified when
  formatting partitions.

  Specifying:
	a: * 0

  would cause a SEGFAULT due the filesystem field not being present.

Fix has been taken from disklabel32.
kernel: Remove drmn leftover.
Remove old drmn.ko module via 'make upgrade'.