accel/habanalabs: expose engine core int reg address

In order for engine cores to raise interrupts towards FW, They need
to know which register the event data should be written to.
Hence, we forward the relevant scratchpad register received during
dynamic regs handshake with FW.

Signed-off-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>