The Senate is giving up NO power. The Senate is deciding to act democratically now, on a simply majority vote, instead of being hobbled by a super-minority, and only for presidential nominations.
Truly inappropriate nominations (ie, Harriet Myers) can still be blocked by majority vote.
The entire filibuster was never laid out in the constitution, it's a convention adopted by the Senate itself and was used ruthlessly by southern racist senators (both Dem and GOP) to block progressive legislation despite being popular and wanted by the majority.