drm/radeon/kms: expose thermal/fan i2c buses

Look up i2c bus in the power table and expose it.
You'll need to load a hwmon driver for any chips
on the bus, this patch just exposes the bus.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index 1484d06..2f917db 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -1165,6 +1165,7 @@
 
 void rv770_fini(struct radeon_device *rdev)
 {
+	radeon_pm_fini(rdev);
 	r600_blit_fini(rdev);
 	r600_cp_fini(rdev);
 	r600_wb_fini(rdev);