habanalabs: add user available interrupt to hw_ip

In order to support completions that arrive directly to the user,
the driver needs to supply the user with the first available msix
interrupt available.

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