dri/radeon: drop obsolete radeon_{dri,macros}.h headers

dri/radeon: drop obsolete radeon_{dri,macros}.h headers

Both have been unused for at least a couple of years.
For example the last user of radeon_macros.h was removed with

commit 8c11f0a88300f7bc3f05a12789c781ba0f4b3cc6
Author: Eric Anholt <eric@anholt.net>
Date:   Fri Oct 14 13:27:02 2011 -0700

    radeon: Drop the legacy BO manager code.

Cc: Marek Olšák <marek.olsak@amd.com>
Cc: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>