Utils: Drop QtcProcess::readyRead signal

Not used anymore.

Change-Id: Icac9ba149f85dfed414df18bfb73e1f46eb9fb1f
Reviewed-by: David Schulz <david.schulz@qt.io>

src/libs/utils/qtcprocess.h

@@ -179,8 +179,6 @@ signals:
 
     void readyReadStandardOutput();
     void readyReadStandardError();
-    void readyRead();
-
 
 private:
     friend class SynchronousProcess;