* videocore/renderer_opengl/gl_rasterizer_cache: Move bits per pixel table out of function
GCC and MSVC copy the table at runtime with the old implementation, which is wasteful and prevents inlining. Unfortunately, static constexpr variables are not legal in constexpr functions, so the table has to be external.
Also replaced non-standard assert with DEBUG_ASSERT_MSG.
* fix case of table name in assert
* set table to private