Revert "net: Add l3mdev index to flow struct and avoid oif reset for port devices"

This reverts commit 740de198 which is
commit 40867d74 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Ib7f4366a88afb45213b068876f0a6c5799562d74
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>