[SCSI] bnx2fc: Reorganize cleanup code between interface_cleanup and if_destory

Move interface specific cleanup functionality to from bnx2fc_if_destroy to
bnx2fc_interface_cleanup. Do not access interface/hba in bnx2fc_if_destroy as
by the time this function is called interface may already be destroyed. This
patch is in preparation to handle NETDEV_UNREGISTER on a vlan device.

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