intel: Throw away 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.

(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!)