[SCSI] bnx2fc: Move offload/upload wait logic into a function

Moved the 'waiting for upload/offload completion' logic to respective
functions as it is called in multiple places. Also this is done in
preperation for the next patch.

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