[PATCH] uml ubd driver: give better names to some functions.

To rethink locking, I needed to understand well what each function does.
While doing this I renamed some:

* ubd_close -> ubd_close_dev (since it pairs with ubd_open_dev)

* ubd_new_disk -> ubd_disk_register (it handles registration with the block
  layer - one hopes this makes clearer the difference with ubd_add())

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>