LCD Controller(s) debug dock suggestion

[Zaalan3]

At the moment, the only debug information that's readily available for the PL111 & ST7789 are in the Misc. dock, and I think it would be very helpful to have a dock for testing and making use of these systems for users developing using something like LCDDRVCE.

An abridged list of things I think such a dock should be capable of:

• Displaying current values for commonly used commands, such as Vertical Scroll, Row/Column Address Set, Gamma Control, etc.
• The ability to as change these values on the fly, to reduce the amount of trial and error required to produce a desired set of commands
• Show current timings for various parts of a frame (For example: Front and Back Porch, Active Video, Per Scanline) for the sake of syncing DMA timing for specific frame rates