Add the missing call to write mInputToken in SurfacePackage to parcel

ag/12396996 introduces mInputToken, but it's only added to parcel
reading. It has thus caused a bug (parcel reading misalignment) in
the Wallpaper app as in our preview feature we passes a
SurfacePackage over from Launcher.

Test: manual
Fixes: 176248059
Change-Id: Ife46d6d67991964d63513c946318cffbaf4ffae9