All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Reciting Al-Faatihah (the opening Chapter of the Quran) or reciting the Names and Attributes of Allaah before the Athaan, or saying the poems praising the Prophet before the Athaan then all this is considered as a religious innovation because it is a newly innovated matter which was not legislated by Allaah nor was it made a Sunnah by the Prophet nor was it done by any of the companions .
The Prophet said: “Whoever does an act that is not in accordance with ours (Islam), it will be rejected.” [Muslim] Therefore, the Mu’aththin (the person who calls the Athaan) whom you mentioned in the question is obliged to repent to Allaah and he should worship Allaah as Allaah and His Messenger willed and not as he wills and innovates.
Whoever knows him or hears him doing that innovation should advise him. The advice should be given to him in a soft and gentle manner. If he stops doing so, then this is what is required, otherwise he should be changed with another Mu’aththin.
For more benefit, please refer to Fatwa before Athaan and Iqaamah">116221.
Allaah Knows best.