[SCSI] bnx2fc: Do not attempt destroying NPIV port twice

When NPIV ports are created/deleted rapidly there is a race condition between
bnx2fc_vport_destroy() from sysfs and bnx2fc_flogi_resp(), which could try to
delete the NPIV port from the list twice. Fix is to loop through the list of
NPIV ports to find a match, and only when it exists remove it.

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