drm/amdkfd: demote unsupported device messages to dev_info

It's not really an error since the devices don't support
the necessary hardware functionality.

Closes: drm/amd#3331


Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Kent Russell <kent.russell@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>