In many cases it's essential to know if the firmware supports a TPM, but in others we should accept it if the firmware doesn't have TPM support, in particular if we want to run the OS with a software TPM. Hence, add tpm2_is_mostly_supported() as function similar to tpm2_is_fully_supported(), with the only difference that the former doesn't insist on a firmware supported TPM. Then, change a number of users over to this (but not all).