To my knowledge there is no MMU (and Im pretty sure). There is a remapping-feature that allows switching between boot ROM and SRAM and you can mark parts of the memory-map to be non-cacheable but this surely has nothing to do with the features a MMU provides.
Concerning TV out on rk2705, the chip has an RGB interface (RGB+Sync signals) which is primarily intended for LCDs but you could of course hook up a DAC or PAL/NTSC encoder to this and get a TV signal. Btw, here is a spec-sheet for the rk2705:
http://www.szxizhuo.com/UploadFiles/...8105248185.pdf.