genxml/gen8: Remove BLACK_LEVEL_CORRECTION_STATE
genxml/gen8: Remove BLACK_LEVEL_CORRECTION_STATE

We've never used it, it only exists on gen8, and the name of the struct
contains piles of bad characters.

Reviewed-by: Chad Versace <4b94d436ff8c93527a96d251ac64b06311506efe@chromium.org>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler