Revert "macsec: Detect if Rx skb is macsec-related for offloading devices that update md_dst"

This reverts commit 21e042d2 which is
commit 642c984d 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: I950792c74cae726b11779d62164947cfafd9c5d7
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>