MAINTAINERS: adjust file entry in GPU BUDDY ALLOCATOR

MAINTAINERS: adjust file entry in GPU BUDDY ALLOCATOR

The commit 4a9671a03f2b ("gpu: Move DRM buddy allocator one level up (part
one)") and commit ba110db8e1bc ("gpu: Move DRM buddy allocator one level up
(part two)") split the majority of the file drivers/gpu/drm/drm_buddy.c
into drivers/gpu/buddy.c, with some pieces remaining in the original
location drivers/gpu/drm/drm_buddy.c.

The commits also adjust the file entries in the GPU BUDDY ALLOCATOR
section, but as part of that, change the file entry to the non-existing
file drivers/gpu/drm_buddy.c instead of keeping the reference to the
existing file drivers/gpu/drm/drm_buddy.c.

Make the file entry in GPU BUDDY ALLOCATOR refer to the intended existing
file. While at it, order the file entries in this section alphabetically.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Reviewed-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Link: https://patch.msgid.link/20260311043314.265627-1-lukas.bulwahn@redhat.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>