netfilter: conntrack: Remove redundant NFCT_ALIGN call

The "nf_ct_tmpl_alloc" function had a redundant call to "NFCT_ALIGN" when
aligning the pointer "p". Since "NFCT_ALIGN" always gives the same result
for the same input.

Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>