netfilter: uapi: NFTA_FLOWTABLE_HOOK is NLA_NESTED

Fix the comment which incorrectly defines it as NLA_U32.

Fixes: 3b49e2e9 ("netfilter: nf_tables: add flow table netlink frontend")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter/nf_tables.h

@@ -1694,7 +1694,7 @@ enum nft_flowtable_flags {
  *
  * @NFTA_FLOWTABLE_TABLE: name of the table containing the expression (NLA_STRING)
  * @NFTA_FLOWTABLE_NAME: name of this flow table (NLA_STRING)
- * @NFTA_FLOWTABLE_HOOK: netfilter hook configuration(NLA_U32)
+ * @NFTA_FLOWTABLE_HOOK: netfilter hook configuration (NLA_NESTED)
  * @NFTA_FLOWTABLE_USE: number of references to this flow table (NLA_U32)
  * @NFTA_FLOWTABLE_HANDLE: object handle (NLA_U64)
  * @NFTA_FLOWTABLE_FLAGS: flags (NLA_U32)