MFC r233000:

MFC r233000:
  Add MODULE_DEPEND() to geom_part modules.

MFC r233342:
  Check that scheme is not already registered. This may happens when a
  KLD is preloaded with loader(8) and leads to infinity loop.

  Also do not return EEXIST error code from MOD_LOAD handler, because
  we have undocumented(?) ability replace kernel's module with preloaded one.
  And if we have so, then preloaded module will be initialized first.
  Thus error in MOD_LOAD handler will be triggered for the kernel.

  PR:		kern/165573

git-svn-id: svn://svn.freebsd.org/base/stable/8@234199 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f