sg: add missing sg_init_table calls to zfcp

kernel BUG at include/linux/scatterlist.h:50!
illegal operation: 0001 [#1]
[...]
Call Trace:
([<000000000026f184>] zfcp_ns_gid_pn_request+0x4c/0x2a0)
 [<0000000000276dd4>] zfcp_erp_strategy_do_action+0x1410/0x1938
 [<0000000000278412>] zfcp_erp_thread+0x4fa/0x1430
 [<000000000001990a>] kernel_thread_starter+0x6/0xc
 [<0000000000019904>] kernel_thread_starter+0x0/0xc

Cc: Swen Schillig <swen@vnet.ibm.com>
Cc: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>

drivers/s390/scsi/zfcp_aux.c

@@ -1518,6 +1518,8 @@ zfcp_gid_pn_buffers_alloc(struct zfcp_gid_pn_data **gid_pn, mempool_t *pool)
                 return -ENOMEM;
 
 	memset(data, 0, sizeof(*data));
+	sg_init_table(&data->req , 1);
+	sg_init_table(&data->resp , 1);
         data->ct.req = &data->req;
         data->ct.resp = &data->resp;
 	data->ct.req_count = data->ct.resp_count = 1;