habanalabs: Add busy engines bitmask to HW idle IOCTL

The information which is currently provided as a response to the
"HL_INFO_HW_IDLE" IOCTL is merely a general boolean value.
This patch extends it and provides also a bitmask that indicates which
of the device engines are busy.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>