v3d: extend the list of formats supported by the TFU unit

This is a backport of !7788 (merged) which extends the list of supported formats in the TFU, with a small difference: here the TFU can be used also to automatically generate the mipmaps, and unfortunately this formats can not be used for that purpose.

Hence, we set here what is the purpose of the usage, so we can tell if the formats are supported or not.