drm/radeon/kms: enable memory clock reading on legacy (V2)

V2: detect IGP cards (which don't have own memory)

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --cc drivers/gpu/drm/radeon/radeon_asic.h
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_clocks.c
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_device.c
Simple merge