accel/habanalabs: do not verify engine modes after being changed

Engines idle state can't always be verified between changes of
engine modes (e.g., stall/halt).
For example, if a CS is inflight when altering engine's mode,
idle state will return NOT idle, always.

Signed-off-by: Koby Elbaz <kelbaz@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>