[PATCH] b44: miscellaneous cleanup

- remove unneeded forward declarations
- s/kmalloc + memset/kzalloc/
- whitespace readjustement can't hurt
- wrong comment: b44_init_rings _is_ called with a spinlock held in
  b44_{open/set_ringparam/set_pauseparam/etc}.
  Actually, it does not need to be able to sleep
- b44_remove_one() can not be issued with a NULL device in its
  private member: remove the test.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>