Here are some minor fixes and cleanups to the cpia (Creative WebCam II et
al) driver.  These have been extracted from the sourceforge CVS archive,
and I'd like to get these in before a larger change to the parallel port
code to support more transfer modes.

This patch contains:
  * cpia: use the <linux/list.h> list implementation, instead of cpia specific
    version.
  * cpia_pp: don't clear camera list after cameras have been registered (as
    this prevents them being deregistered, and oops after module
    unload).
  * hold cpia_pp list spinlock while walking list, not just during the
    element removal.