vulkan: Mark remaining single argument ctors explicit

Bug: none
Test: compile

Change-Id: I6bc5009527bdf9efbfc5fe935aa86856ee491711
Reviewed-on: https://chromium-review.googlesource.com/1061396
Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Michael Spang <spang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559199}
2 files changed