a693a2998c
i965 can either do SRGBA8_REV format or SARGB8 format, but not SRGBA8. Could add SRGBA8_REV support to mesa, but simply use SARGB8 for now. While here, also add true srgb luminance / luminance_alpha support - unfortunately the published docs fail to mention which asics support this, tested on g43 so assume this works on any g4x.