It appears this is a mistake, since the sub-screen has no right
framebuffer.

PDC0 and PDC1 are both VBlank interrupts. PDC0 was being treated as a
HBlank interrupt and fired many more times than it should. They now both
fire together at 60 Hz. This puzzlingly *improves* apparent framerate on
many applications.

A few other interrupts were being fired inside the GSP command
processing instead of on the actual GPU register writes, so they were
moved there, which should cover direct writes tho those registers not
going through the GX command queue.

- Hack to work around games checking that the DSP event has been signaled by a real DSP interrupt.

It's not really known how this actually works. Some testing has shown that this probably performs no filtering, and common usage in games suggests it's not actually resizing the image at all.
However, this patch does seem to fix some homebrew showing quasi-duplicated images while still keeping other applications in a working state.

This name better represents what the enum does, and is less overloaded
in the context. (The whole register the enum is part of is also called
'format'.)

GPU: Improve frame synchronization, increases compatibility with both homebrew and retail applications.

This cleans up the mess that address reading/writing had become and makes the code a *lot* more sensible.
This adds a physical<->virtual address converter to mem_map.h. For further accuracy, we will want to properly extend this to support a wider range of address regions. For now, this makes simply homebrew applications work in a good manner though.

While it was some nice and fancy template usage, it ultimately had many practical issues regarding length of involved expressions under regular usage as well as common code completion tools not being able to handle the structures.
Instead, we now use a more conventional approach which is a lot more clean to use.

GPU: Updated g_last_ticks variable to be more descriptive (represents CPU tick count of last vertical line).

- Various other cleanups.

Core: Added a comment to explain the logic for the RunLoop iterations.

Also makes the illogical component order more obvious.