sensor: Enable RTIO Semaphores for Async API

In order to decouple the read request from its implementation, we need
to be able to yield to potential lower-priority threads, which is not
possible with k_yield() itself. As such, using RTIO Consume semaphore
enables us to achieve this.

This patch also refactors blocking API (sensor_read) to also block upon
consumption, so as not to require RTIO_SUBMIT_SEM enabled.

Signed-off-by: Luis Ubieda <luisf@croxel.com>