Getting IEGD DRM changes into the main tree is something that we have wanted to do, but just did not have the resources to push it. The thinking is that the utility to make our unique changes (IKM) exists and is provided in source for anyone to tweak is "good enough" for the situation. Trying to track the kernel changes and keeping our needs represented in the source would be a full time effort and we would rather spend those resources on the driver itself.
Also, there are changes in the works that affect our use of the DRM and when complete that may be the right time to push to get it into the main kernel tree.
Thanks for the idea, I hope this information helps.