gma500: kill MIPI interface types

Kirill Shutemov found problems with the non-upstream IMG driver where the
use of extra DRM encoder/connector types caused random crashes when the DRM
layer tried to display their matching name. This removes the MIPI types
matching the changes Pauli Nieminen made to the non upstream driver set.

As Pauli points out:
" MIPI (or DSI) is protocol specification on top of LVDS serial bus. That
 makes it resonable to call MIPI connectors and encoders LVDS."

(and indeed they may also be HDMI convertors or similar when we want to
 report a more useful to end user result)

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>