[SCSI] ibmvscsi: handle large scatter/gather lists

The maximum size of a scatter-gather list that the current IBM VSCSI
Client can handle is 10.  This patch adds large scatter-gather support
to the client so that it is capable of handling up to SG_ALL(255)
number of requests in the scatter-gather list.
Signed-off-by: Linda Xie <lxie@us.ibm.com>
Acked by: Dave C Boutcher <sleddog@us.ibm.com>

Rejections fixed up and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/ibmvscsi/ibmvscsi.h

@@ -68,6 +68,8 @@ struct srp_event_struct {
 	void (*cmnd_done) (struct scsi_cmnd *);
 	struct completion comp;
 	union viosrp_iu *sync_srp;
+	struct memory_descriptor *ext_list;
+	dma_addr_t ext_list_token;
 };
 
 /* a pool of event structs for use */