i965g: pass relocation information in an array with bo_subdata

i965g: pass relocation information in an array with bo_subdata

Makes it easier to dump as we get all of the information
about the upload in a single hit.

Opens the window to simplification in the driver if these
relocation arrays can be maintained statically rather than
being recreated whenever we check for a new upload.

Still needs some cleanup to avoid uglyness introduced with the
delta values.