hpsa: refactor duplicated scan completion code into a new routine

Hoist the conditional out of do_not_scan_if_controller_locked_up() and
place it in the caller (this improves the code structure, making it
more consistent with other uses and enabling tail-call optimization);
rename the function to hpsa_scan_complete(), and use it at the end of
hpsa_scan_start() as well.

Reviewed-by: Scott Teel <scott.teel@pmcs.com>
Signed-off-by: Webb Scales <webbnh@hp.com>
Signed-off-by: Don Brace <don.brace@pmcs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>