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

This reverts commit 5bcde9b4 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: I8007fbec296ed48395d7c1f03100be840de1732f
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>