netfilter: nft_masq: correct length for loading protocol registers

netfilter: nft_masq: correct length for loading protocol registers

[ Upstream commit 5a34fd291975e2d5ae04041ab01ccdcb15ffcaeb ]

The values in the protocol registers are two bytes wide.  However, when
parsing the register loads, the code currently uses the larger 16-byte
size of a `union nf_inet_addr`.  Change it to use the (correct) size of
a `union nf_conntrack_man_proto` instead.

Fixes: c046ad4f3bbe ("netfilter: nft_masq: support port range")
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>