drm/radeon: load the lm63 driver for an lm64 thermal chip.

commit 5dc355325b648dc9b4cf3bea4d968de46fd59215 upstream.

Looks like the lm63 driver supports the lm64 as well.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>