openvswitch: avoid cast-qual warning in vport_priv

This function must cast a const value to a non const value.
By adding an uintptr_t cast the warning is suppressed.
To avoid the cast (proper solution) several function signatures
must be changed.
Signed-off-by: Daniele Di Proietto <daniele.di.proietto@gmail.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

net/openvswitch/vport.h

@@ -172,7 +172,7 @@ void ovs_vport_deferred_free(struct vport *vport);
  */
 static inline void *vport_priv(const struct vport *vport)
 {
-	return (u8 *)vport + ALIGN(sizeof(struct vport), VPORT_ALIGN);
+	return (u8 *)(uintptr_t)vport + ALIGN(sizeof(struct vport), VPORT_ALIGN);
 }
 
 /**