nf_conntrack: padding breaks conntrack hash on ARM

nf_conntrack: padding breaks conntrack hash on ARM

[NETFILTER]: nf_conntrack: padding breaks conntrack hash on ARM

Upstream commit 443a70d50:

commit 0794935e "[NETFILTER]: nf_conntrack: optimize hash_conntrack()"
results in ARM platforms hashing uninitialised padding.  This padding
doesn't exist on other architectures.

Fix this by replacing NF_CT_TUPLE_U_BLANK() with memset() to ensure
everything is initialised.  There were only 4 bytes that
NF_CT_TUPLE_U_BLANK() wasn't clearing anyway (or 12 bytes on ARM).

Signed-off-by: Philip Craig <philipc@snapgear.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>