[NET] rtnetlink.c: remove no longer used functions

This patch removes the following no longer used functions:
- rtattr_parse()
- rtattr_strlcpy()
- __rtattr_parse_nested_compat()

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/linux/rtnetlink.h
Simple merge

diff --cc net/core/rtnetlink.c
Simple merge