[CrOS MultiDevice] Remove kMultiDevice API flags from smart lock code.

Removing kMultiDevice flags and associated code paths that will
no longer occur.

Bug: 912743
Change-Id: Iabb917876b570b8df953f22a30eb05787a5ef1ef
Reviewed-on: https://chromium-review.googlesource.com/c/1370485
Commit-Queue: Regan Hsu <hsuregan@chromium.org>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Reviewed-by: James Hawkins <jhawkins@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615393}
8 files changed