ipv4: Don't store a rule pointer in fib_result.

We only use it to fetch the rule's tclassid, so just store the
tclassid there instead.

This also decreases the size of fib_result by a full 8 bytes on
64-bit.  On 32-bits it's a wash.

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

diff --cc include/net/ip_fib.h
Simple merge

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

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

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