cciss: remove redundant code

This patch removes redundant code where ever logical volumes are added or
removed. It adds 3 new functions that are called instead of having the same
code spread throughout the driver. It also removes the cciss_getgeometry
function.
The patch is fairly complex but we haven't figured out how to make it any
simpler and still do everything that needs to be done. Some of the
complexity comes from having to special case booting from cciss. Otherwise
the gendisk doesn't get added in time and the switchroot will fail.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
Signed-off-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>