[Intel-gfx] [PATCH] drm/i915: Remove unreachable code

[Chris Wilson]

Quoting Vinicius Tinti (2021-01-29 18:15:19)
> By enabling -Wunreachable-code-aggressive on Clang the following code
> paths are unreachable.

That code exists as commentary and, especially for sdvo, library
functions that we may need in future.

The ivb-gt1 case => as we now set the gt level for ivb, should we not
enable the optimisation for ivb unaffected by the w/a? Just no one has
taken the time to see if it causes a regression.

For error state, the question remains whether we should revert to
uncompressed data if the compressed stream is larger than the original.
-Chris