intel/blorp: Stop using the X/YOffset field of RENDER_SURFACE_STATE

intel/blorp: Stop using the X/YOffset field of RENDER_SURFACE_STATE

While it can be useful, the field has substantial limtations.  In
particular, the bittom 2 or 3 bits is missing so your offset always has to
be a multiple of 4 or 8.  While surface alignments usually work out to make
this ok, when you start trying to fake compressed surfaces as uncompressed
(which we will want to do) this falls apart.  The easiest solution is to
simply align all offsets to a tile boundary and munge the regions we're
copying to account for the intratile offset.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>