Bid'ah

Azaan at the Grave Site

Q: I am reading a book called "Death The Final Journey" by Muhammad Abd Al -Mannan. In this book he states that its Sunnat to give Azaan at the grave site quoting Abu Hurairah (Radiyallahu Anhu) in Muslim and Buhkari Sherif. Further he states that in Durre Muktar its sunnat to give Azaan at the grave with it's blessings the Shaytan will run?