drm/radeon/kms/atom: Make card_info per device

Make the struct card_info, which is a per struct radeon_device dataset, a
struct member of the radeon device instead of a static per kernel module
value. This should avoid potential problems with two radeon cards installed in
one system.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>