Adjust rt speed steps.

This commit adjusted the speed steps in rt mode to make the steps
more evenly spaced on speed and quality, specifically:
1. Merged 3 and 4 into one single step 3 and removed confilicting
features.
2. Move 8, 7, 6, 5 to be 7, 6, 5, 4 repsectively.

Change-Id: I38d56d61531f3561d772aef953c411c8fb38c063