The Prophet ﷺ said, "Tawaf is indeed a form of prayer, so when you perform it, speak little." Muhammad bin Bakr did not raise this hadith to the Prophet.
حدثنا عبد الرزاق وروح قالا حدثنا ابن جريج قال أخبرني حسن بن مسلم عن طاوس
أن النبي ﷺ قال إنما الطواف صلاة فإذا طفتم فأقلوا الكلام ولم يرفعه محمد بن بكر
Its chain of transmission is sahih. Hasan bin Muslim bin Yanaq Makki is trustworthy by consensus, and Tawus is a well known trustworthy narrator. Ahmad indicated that it is mawquf according to the route of Muhammad bin Bakr Barsani.The hadith was narrated similarly by Tirmidhi (3/284, no. 960) in the book of Hajj, chapter on what has been said about speaking during tawaf, where he indicated that only Ataa raised it to Ibn Abbas as a marfu narration. It was also narrated by Nasai (5/222, no. 2922) in the book of Hajj, chapter on the permissibility of speaking during tawaf, and by Darimi (2/66, no. 1847) similarly, and by Hakim (1/459), with Dhahabi agreeing with him, though he said, "A group of narrators reported it as mawquf," referring to the route of Muhammad bin Bakr. It was also narrated by Bayhaqi (5/87).