Revert "net: fix dev_fill_forward_path with pppoe + bridge"

This reverts commit f96b2e06.

It breaks the ABI and will be brought in through a different branch to
preserve it.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I729afbaefb667bd9e73260efb83c68e434e5bce6