No regressions on IVB (piglit quick + unit tests).

v2 (Paul):
  - no need to patch the unit tests anymore. Original logic
    was altered and unit tests updated to match the
    fs-generator
  - lrp emission moves from the blorp compiler core into the
    emitter here (previously there was a separate refactoring
    patch which is not really needed anymore as the lrp logic
    got refactored when the original lrp logic got fixed).
  - pass 'BRW_BLORP_RENDERBUFFER_BINDING_TABLE_INDEX' to the
    generator in fs_inst::target instead of hardcoding it

Signed-off-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
Reviewed-by: Paul Berry <stereotype441@gmail.com>