[Intel-gfx] Updated stolen mem patches

[Jesse Barnes]

These address the comments I've received so far, but omit the new E820
type for this mem.

Chris's patches could go on top if desired; they add a new type and
resource reservation function for looking up regions by name.  That
allows us to remove some duplicate code in the driver for finding stolen
space.

But I think these two are ready as-is.  How should we merge them?  Just
through the i915 tree since the first one touches our headers?  that and
there probably won't be conflicts on the early-quirks file; that's not
touch too often...

Thanks,
Jesse