Change in libgfxinit[master]: hw-gfx-gma: Use Broxton panel registers for CFL+

[Angel Pons (Code Review)]

Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/libgfxinit/+/46625 )

Change subject: hw-gfx-gma: Use Broxton panel registers for CFL+
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Patch Set 4:
> Patch Set 4:
>
> (1 comment)
>
> We just learned that Coffee Lake can be paired with a
> 200 series PCH. In this case, the current code would
> match, but this change would break it.
>
> So this asks for a more comprehensive solution. I'm
> afraid, we'll have to add `PCH` type. Or maybe let's
> call it `Chipset`? That would better apply to all
> generations (also G45, and the small core SoCs). We
> could have the chipset in Kconfig and derive the
> generation from that internally.

Agreed. This change would need better handling to account for CFL+UPT.