[SCSI] bfa: scatter gather processing change

Modified scatter gather processing to use the kernel provided
scsi_for_each_sg() macro.

1) Instead of allocating and setting up sgpg in bfa_ioim_sge_setup(),
   we only do allocation.  As a result, we remove
   bfa_ioim_sgpg_setup() and rename bfa_ioim_sge_setup() to
   bfa_ioim_sgpg_alloc().

2) bfa_ioim_send_ioreq() call scsi_for_each_sg() to handle both inline
   and sgpg setup.

Signed-off-by: Maggie Zhang <xmzhang@brocade.com>
Signed-off-by: Jing Huang <huangj@brocade.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>