VibratorService: Conditionally Use Callbacks

VTS is enforcing that HALs return error if the callback is not null and
callbacks are not supported.

Bug: 137601983
Test: Manually on devices with and without callback support.
Change-Id: Iada3a4189f8e0986e7894f4bcdc3d9c309d313d8
Signed-off-by: Harpreet \"Eli\" Sangha <eliptus@google.com>
2 files changed