spapr_vscsi: Set uninitialized variable

cppcheck reports this error:

hw/spapr_vscsi.c:274: error: Uninitialized variable: rc

If llen == 0, rc was indeed used without being initialized.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NAlexander Graf <agraf@suse.de>

hw/spapr_vscsi.c

@@ -255,7 +255,7 @@ static int vscsi_srp_direct_data(VSCSIState *s, vscsi_req *req,
 {
     struct srp_direct_buf *md = req->cur_desc;
     uint32_t llen;
-    int rc;
+    int rc = 0;
 
     dprintf("VSCSI: direct segment 0x%x bytes, va=0x%llx desc len=0x%x\n",
             len, (unsigned long long)md->va, md->len);