What is the difference between a 'baseband processor' and 'baseband controller'?
The difference, if there is one, is manufacturer specific.  A baseband processor and a baseband controller often perform the same functions - that of controlling every aspect of the RF hardware.  

Some manufacturers like to use "baseband processor" in order to  indicate that their controller performs functionality you might find higher on a communications stack, such as message decoding.  For instance a WiFi baseband controller might still need to be attached to a processor to implement a full WiFi link, whereas a baseband processor might handle more of the communications stack and may attach directly to another network interface, USB, etc.