(Ag Adjustment Act provision contained in 7 U.S.C. Sec. 1359dd(b)(2)(E)-(F) unambiguous and USDA's regulatory interpretation not entitled to deference; under Act, "processor" is an entity who processes sugar and Act requires USDA to eliminate processor's sugar marketing allocation when processor permanently terminates operations; Pacific Northwest Sugar Company permanently terminated operations before sale of assets to plaintiff and USDA erred in approving transfer of allocation to another sugar company; subject sugar marketing allocation must be redistributed pro rata among all sugar processors).