[infiniband] Rename IB_PKEY_NONE to IB_PKEY_DEFAULT

There is no such thing as a non-existent partition.

src/include/gpxe/infiniband.h

 #define IB_QPN_BROADCAST 0xffffffUL
 
 /** Default Infiniband partition key */
-#define IB_PKEY_NONE 0xffff
+#define IB_PKEY_DEFAULT 0xffff
 
 /**
  * Maximum payload size

src/net/infiniband.c

 		INIT_LIST_HEAD ( &ibdev->qps );
 		ibdev->port_state = IB_PORT_STATE_DOWN;
 		ibdev->lid = IB_LID_NONE;
-		ibdev->pkey = IB_PKEY_NONE;
+		ibdev->pkey = IB_PKEY_DEFAULT;
 	}
 	return ibdev;
 }

src/net/infiniband/ib_srp.c

 			       struct ib_srp_root_path *rp ) {
 	int pkey;
 
-	if ( ( pkey = ib_srp_parse_integer ( rp_comp, IB_PKEY_NONE ) ) < 0 )
+	if ( ( pkey = ib_srp_parse_integer ( rp_comp, IB_PKEY_DEFAULT ) ) < 0 )
 		return pkey;
 	rp->ib->pkey = pkey;
 	return 0;