TPM chip on iPhone
I'm assuming that your TPM reference stands for "Trusted Platform Module."
According to Wikipedia:
Due to legal restrictions TPMs may not be deployed in a number of countries. Possible reasons for these legal restrictions include the fact that state security services may not be able to access data or keys secured with a TPM.
- China
- Russia
- Belarus
- Kazakhstan
Since Apple sells iPhones in China (see this NY Times article), we can infer that the iPhone doesn't ship with TPM chips.
See https://www.apple.com/business/docs/iOS_Security_Guide.pdf especially the part about the 'Secure Enclave' coprocessor.
All the Apple S2, Apple A7, and later A-series seem to have such a co-processor.
As stated here it's essentially a TPM: https://news.ycombinator.com/item?id=10918999
Though I guess you could still argue that, especially when not knowing the exact architecture and inner workings of this chip.
I can't (couldn't, see below update) find any mention of a "... unique and secret RSA key burned in as it is produced ..." (Wikipedia, 2017) inside the enclave processor for example. But I guess you could do more research ;)
Update 2-11-2021:
Below is a quote / excerpt from the 'secure enclave' description page.
Root Cryptographic Keys
The Secure Enclave includes a unique ID (UID) root cryptographic key. The UID is unique to each individual device and isn’t related to any other identifier on the device.
A randomly generated UID is fused into the SoC at manufacturing time. Starting with A9 SoCs, the UID is generated by the Secure Enclave TRNG during manufacturing and written to the fuses using a software process that runs entirely in the Secure Enclave. This process protects the UID from being visible outside the device during manufacturing and therefore isn’t available for access or storage by Apple or any of its suppliers.
BTW: I'm not sure if (and how) the presence of the 'Secure Enclave' chip inside iPhones might be affected by the legal restrictions that country's have as @JW8 so clearly states in his answer.