i915: No longer rely on compatability define in intel_bufmgr.h

Symbol rename from dri_* to drm_intel_* introduced a number of compatability
defines within intel_bufmgr.h.

Replace the old function with the new function, consistent with the balance
of this file.

Signed-off-by: Rhys Kidd <rhyskidd@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
1 file changed