habanalabs: restore unsecured registers default values

unsecured registers can be changed by the user, and hence should be
restored to their default values in context switch

Signed-off-by: Dalit Ben Zoor <dbenzoor@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>