netfilter: add missing xt_bpf.h header in installation

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter/Kbuild

@@ -35,6 +35,7 @@ header-y += xt_TCPOPTSTRIP.h
 header-y += xt_TEE.h
 header-y += xt_TPROXY.h
 header-y += xt_addrtype.h
+header-y += xt_bpf.h
 header-y += xt_cluster.h
 header-y += xt_comment.h
 header-y += xt_connbytes.h