drm/nv50: import initial clock get/set routines + hook up pm engine

This will make nouveau_pm attempt to report the card's current performance
level both during bootup, and through sysfs.

This is a very initial implementation, and can be improved a *lot*

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_pm.h

@@ -41,4 +41,9 @@ int  nouveau_voltage_gpio_set(struct drm_device *, int voltage);
 void nouveau_perf_init(struct drm_device *);
 void nouveau_perf_fini(struct drm_device *);
 
+/* nv50_pm.c */
+int nv50_pm_clock_get(struct drm_device *, u32 id);
+void *nv50_pm_clock_pre(struct drm_device *, u32 id, int khz);
+void nv50_pm_clock_set(struct drm_device *, void *);
+
 #endif