[NET]: Do not memcmp() over pad bytes of struct flowi.

They are not necessarily initialized to zero by the compiler,
for example when using run-time initializers of automatic
on-stack variables.

Noticed by Eric Dumazet and Patrick McHardy.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc net/decnet/dn_route.c
Simple merge

diff --cc net/ipv4/route.c
Simple merge