You're fine. It won't hurt the batch. Depending on the gravity of the wort you could probably get away with pitching only half, though, especially if you had another similar sized batch to pitch the remaining yeast into. (Probably the incurably tight Scots' upbringing in me coming out
What kind of yeast and style of beer is it? Some styles can benefit from a slight underpitch which stresses the yeast into producing esters that are desirable in that style.