op-node: Use background context (#3718)

op-node/rollup/driver/state.go

@@ -309,9 +309,7 @@ func (s *Driver) eventLoop() {
 			s.metrics.SetDerivationIdle(false)
 			s.idleDerivation = false
 			s.log.Debug("Derivation process step", "onto_origin", s.derivation.Origin(), "attempts", stepAttempts)
-			stepCtx, cancel := context.WithTimeout(ctx, 20*time.Minute) // TODO pick a timeout for executing a single step
-			err := s.derivation.Step(stepCtx)
-			cancel()
+			err := s.derivation.Step(context.Background())
 			stepAttempts += 1 // count as attempt by default. We reset to 0 if we are making healthy progress.
 			if err == io.EOF {
 				s.log.Debug("Derivation process went idle", "progress", s.derivation.Origin())