build: fix compile error with no macvtap

Since commit 6ec8288a, compilation has failed on RHEL 5:

util/virnetdevmacvlan.c:672: error: conflicting types for 'virNetDevMacVLanCreateWithVPortProfile'

* src/util/virnetdevmacvlan.c
(virNetDevMacVLanCreateWithVPortProfile): Add missing parameter.

src/util/virnetdevmacvlan.c

@@ -662,6 +662,7 @@ int virNetDevMacVLanCreateWithVPortProfile(const char *ifname ATTRIBUTE_UNUSED,
                                            const unsigned char *macaddress ATTRIBUTE_UNUSED,
                                            const char *linkdev ATTRIBUTE_UNUSED,
                                            enum virNetDevMacVLanMode mode ATTRIBUTE_UNUSED,
+                                           bool withTap ATTRIBUTE_UNUSED,
                                            int vnet_hdr ATTRIBUTE_UNUSED,
                                            const unsigned char *vmuuid ATTRIBUTE_UNUSED,
                                            virNetDevVPortProfilePtr virtPortProfile ATTRIBUTE_UNUSED,