media: platform: amd: low level support for isp4 firmware

media: platform: amd: low level support for isp4 firmware

Low level functions for accessing the registers and mapping to their
ranges. This change also includes register definitions for ring buffer
used to communicate with ISP Firmware. Ring buffer is the communication
interface between driver and ISP Firmware. Command and responses are
exchanged through the ring buffer.

Co-developed-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
Signed-off-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
Signed-off-by: Bin Du <Bin.Du@amd.com>
Reviewed-by: Sultan Alsawaf <sultan@kerneltoast.com>
Tested-by: Alexey Zagorodnikov <xglooom@gmail.com>
Tested-by: Kate Hsuan <hpa@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>