Not possible, no such Speed Booster exists. Yiu can not have an adapter between a EF Mount Camera and an EF lens, yiu do not have any difference in the FFD (focal flange distance) to accommodate the optical block. A Speed Booster is a focal reducer, think opposite of a Tele Converter, and needs a difference of FFD between a camera mount and a longer FFD lens mount, like MFT Camera (very short FFD) to a Nikon or Canon EF Mount (much longer FFD).
So Speed Boosters like the Metabones BMCC MFT Speed Booster work between the camera MFT mount and the EF or Nikon F lens mount. Speed boosters are also available for Sony E mount, which is shorter than the MFT mount.
Cheers