Revert "xfrm: store and rely on direction to construct offload flags"

This reverts commit 76ff31c0 which is
commit 482db2f1 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: I88d9803ece3fbc9b01a2430d6f32d6fd26d2ea68
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>