Paul wrote the book of Galatians before he wrote 1 Corinthians. For those of you who think that Paul preached a separate gospel from that of Peter, don't you think he would have mentioned something about that to the Corinthians? But he does not! Instead, this is what he says:
1 Cor 1:10-13, 3:1-4, 11, 21-23, 4:6
Now I plead with you, brethren, by the name of our Lord Jesus Christ, that you all agree and that there be no divisions among you. What I mean is that each one of you says "I follow Paul" or "I follow Peter". Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul? But I, brethren, could not address you as spiritual men, but as men of the flesh, as infants in Christ. For when one says, "I follow Paul", or "I follow Apollos", are you not mere men? For no other foundation can anyone lay than that which is laid, which is Jesus Christ, so let no one boast of men. For all things are yours, whether Paul or Apollos or Peter. And you are Christ's, and Christ is God's. This is how one should regard us: as servants of Christ and stewards of the mysteries of God, that none of you may be puffed up in favor of one against another.
Again, Paul wrote all of that after he wrote Galatians 2:11-21, which is proof that they cleared that issue up with each other before Paul wrote 1 Corinthians. It can clearly be seen from the above passages that Paul viewed himself and Peter as fellow "servants of Christ and stewards of the mysteries of God". Furthermore, Paul said that those who do draw a dividing line between himself and Peter are immature, carnal and unspiritual.