r600: GLES3 RGB pbo test broken [bisected]
The commit 0899bf55 st/mesa: Map MESA_FORMAT_RGB_UNORM8 <-> PIPE_FORMAT_R8G8B8_UNORM
broke a number of CTS gles3 tests on r600/CEDER e.g. dEQP-GLES3.functional.texture.specification.texsubimage3d_pbo.rgb8_image_height_2d_array
the error pattern indicates that some alignment might be off when sending the data around.