Phonet: declare headers

Signed-off-by: Rémi Denis-Courmont <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/Kbuild

···
 header-y += pfkeyv2.h
 header-y += pg.h
 header-y += phantom.h
+header-y += phonet.h
 header-y += pkt_cls.h
 header-y += pkt_sched.h
 header-y += posix_types.h
···
 unifdef-y += if_frad.h
 unifdef-y += if_ltalk.h
 unifdef-y += if_link.h
+unifdef-y += if_phonet.h
 unifdef-y += if_pppol2tp.h
 unifdef-y += if_pppox.h
 unifdef-y += if_tr.h