habanalabs: Add descriptive names to PSOC scratch-pad registers

The PSOC scratch-pad registers are used for communication with the
device CPU. This patch adds new definitions for these registers which
are more descriptive than their general names.

The new set of definitions also gathers and documents the current usage
of the scratch-pad registers by the driver and the device CPU.

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>