uapi: export nf_log.h

File is in uapi directory but not being copied on
 make install_headers

Fixes commit 4ec9c8fbbc22 ("netfilter: nft_log: complete
NFTA_LOG_FLAGS attr support").
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/netfilter/Kbuild

@@ -5,6 +5,7 @@ header-y += nf_conntrack_ftp.h
 header-y += nf_conntrack_sctp.h
 header-y += nf_conntrack_tcp.h
 header-y += nf_conntrack_tuple_common.h
+header-y += nf_log.h
 header-y += nf_tables.h
 header-y += nf_tables_compat.h
 header-y += nf_nat.h