habanalabs: send device activity in a proper context

'Device activity open packet' should be sent outside of mutex as
there is no real necessity for a lock.
In addition 'device activity close packet' should be sent upon an
actual release of the device.

Signed-off-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>