Add DRM DP support on i1200

This MR adds DRM DP over USB-C support on i1200

It uses Display-port over USB-C work from Fabien and the latest mmsys/vdosys code from Mediatek

At the moment I can see a couple of issues:

• weston display issues (that may not be related to this code)
• unplugging and plugging again on the same screen won't work (it works if you change screen)

Requires the following config to be added: CONFIG_TYPEC_DP_ALTMODE=m

Note that a few hacks like the "dtbo merged into dts", the "temp remove dp_intf1 on ext_path" will need to be cleaned

EDIT 22/05/16:

• this MR is to be merged on top of MR 424
• all the known issues are fixed at the moment

JIRA: AIOT-767