MAINTAINERS: Update mailing list for radeon and amdgpu

amdgpu and radeon development has moved to this list.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Alex Deucher 2016-12-19 13:30:13 -05:00
commit 7f4c4f80fd