ashmemd: avoid sleep cycle on non-VNDK devices.

On non-VNDK device (e.g. sailfish) the code path to ashmemd is the same,
which results in vendor processes always failing to get ashmemd service.
Use checkService() to fail immediately, instead of waiting for the
service.

Fixes: 123999623
Test: boot sailfish, no sleep cycles when trying to reach ashmemd.
Change-Id: I4fce14fad28b509cd112370bc4cc2eafd45c6c75