Don't worry about it, that's a common problem and there's no need to file I-90. Just write your correctly spelled name on the N-400 where it asks for your current legal name, and write the incorrect GC name where it asks for the name as displayed on the green card.
You will have to bring another document with your correct name to resolve the discrepancy; normally they will ask for your birth certificate. Or your marriage certificate, if your last name changed due to marriage.
EB3 ROW I-485 Approved: July 2007
USC: July 2013
I am a layman, not a lawyer. What I write here is not official or professional legal advice. In addition, my answers on this forum are specific to the scenarios discussed in each thread and should not be generalized to other situations.