ANDROID: GKI: workqueue.h: add Android ABI padding to some structures

Try to mitigate potential future driver core api changes by adding a
padding to struct work_struct and struct delayed_work

Based on a change made to the RHEL/CENTOS 8 kernel.

Bug: 151154716
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I5492a13e2430c1a5775aec52518144b7aa4f3268