Revert "bpf, sockmap: Convert schedule_work into delayed_work"

This reverts commit 9f4d7efb.

It breaks the Android KABI and will be brought back at a later time when
it is safe to do so.

Bug: 161946584
Change-Id: Ic3e8a533b0958aea3b2f58af8aa8292377e78ace
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>