[qcms] Reduce RMS color error for qcms_transform_data_rgb(a)_out_lut

Before this CL:

Input profile sRGB IEC61966-2.1
Output profile Adobe RGB (1998) (using qcms precache)
RMS color error 2.66

Input profile Adobe RGB (1998)
Output profile sRGB IEC61966-2.1 (using qcms precache)
RMS color error 0.94

After this CL:

Input profile sRGB IEC61966-2.1
Output profile Adobe RGB (1998) (using qcms precache)
RMS color error 2.66

Input profile Adobe RGB (1998)
Output profile sRGB IEC61966-2.1 (using qcms precache)
RMS color error 0.87

TODO: Make software and SSE bit exact?

BUG=532910

Review URL: https://codereview.chromium.org/1414493004

Cr-Commit-Position: refs/heads/master@{#358581}
3 files changed