[SCSI] bnx2fc: Bug fixes in percpu_thread_create/destroy

Look up p->work_list to process cq completions, and correct the error check for
thread creation.

Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>