tcm_vhost: Change vhost_scsi_target->vhost_wwpn to char *

This patch changes the vhost_scsi_target->vhost_wwpn[] type used
by VHOST_SCSI_* ioctls to 'char *' as requested by Blue Swirl in
order to match the latest QEMU vhost-scsi RFC-v3 userspace code.

Queuing this up into target-pending/master for a -rc3 PULL.
Reported-by: Blue Swirl <blauwirbel@gmail.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/vhost/tcm_vhost.h

@@ -91,7 +91,7 @@ struct tcm_vhost_tport {
 
 struct vhost_scsi_target {
 	int abi_version;
-	unsigned char vhost_wwpn[TRANSPORT_IQN_LEN];
+	char vhost_wwpn[TRANSPORT_IQN_LEN];
 	unsigned short vhost_tpgt;
 };