I must say, I don't really like this patch. It seems like it's just trying
to let you avoid writing two reloc functions which should, by and large, be
no-ops for iris.That said, the way blorp does surface relocs is really
annoying because it forces the reloc function to write in the value.
Drivers using softpin do not need (or have) relocations. The old
relocation interface is somewhat awkward and limiting.
In particular, brw_surface_reloc assumes that all SURFACE_STATEs will
exist in a single buffer, and only provides ss_offset. The driver is
supposed to implicitly know about
