gallium/radeon: fix incorrect bpe use in si_set_optimal_micro_tile_mode
gallium/radeon: fix incorrect bpe use in si_set_optimal_micro_tile_mode

Oh my god, I wonder what catastrophic issues this was causing on SI.

Cc: 13.0 <59f39c0db42d4479a46b02d4d2bc11120e37bb44@lists.freedesktop.org>
Reviewed-by: Bas Nieuwenhuizen <1d31d94f30d40df7951505d1034e1e923d02ec49@basnieuwenhuizen.nl>
Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler