intel: Add the ability to supply annotations for .aub files.

This patch adds a new function,
drm_intel_bufmgr_gem_set_aub_annotations(), which can be used to
annotate the type and subtype of data stored in various sections of
each buffer.  This data is used to populate type and subtype fields
when generating the .aub file, which improves the ability of later
debugging tools to analyze the contents of the .aub file.

If drm_intel_bufmgr_gem_set_aub_annotations() is not called, then we
fall back to the old set of annotations (annotate the portion of the
batchbuffer that is executed as AUB_TRACE_TYPE_BATCH, and everything
else as AUB_TRACE_TYPE_NOTYPE).

Reviewed-by: Eric Anholt <eric@anholt.net>