CBS' NCAA Tournament coverage of the regional semifinals delivered a significant week-to-week ratings bump, dominating Thursday’s primetime as expected. Early nationals indicate a 2.0 demo rating and 6.618 million total viewers, but those stats will change significantly because they are not time zone-adjusted. In metered-market results, CBS' primetime clocked a 4.5 household rating, which is up 2% from last year's 4.4 on the comparable Thursday. ABC's TGIT held the…