Remove the clock view when DISABLE_CLOCK is set

Gets rid of Floating Notification Syndrome™

The easiest way to see this is launching SUW or pinned-task mode with
debug.layout set to true, and see that there is no box containing the
clock in these modes

Test: visual;
Change-Id: I518bc04d2dca2fb56f13e0cebc475929edaf2c48
Fixes: 77630482