intel: Finish off the last scraps of bacon

intel: Finish off the last scraps of bacon

The bacon is long past its expiration date and has got to go.
Composting it in the flower-beds was probably inadvisable.
So we shall throw it away.

(Originally, I imported libdrm_intel into i965, but to avoid symbol
conflicts, renamed drm_intel_* to drm_bacon_* as it was the same number
of letters and we needed an arbitrary name.  After slicing-and-dicing
away most of the fat, er, code, we renamed it to brw_bufmgr...except
for apparently this comment, which then got replicated to both iris
and crocus.  Originally it served to indicate what file contained these
functions, but bufmgr.h having prototypes for bufmgr.c is obvious, so
just delete the silly comment.  No bacon for you!)

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12985>