drm/nouveau: move out of staging drivers

There's really no good reason for us to be in here anymore, we have to
maintain this ABI anyway to avoid angering people.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/Kconfig

@@ -71,6 +71,8 @@ config DRM_RADEON
 
 source "drivers/gpu/drm/radeon/Kconfig"
 
+source "drivers/gpu/drm/nouveau/Kconfig"
+
 config DRM_I810
 	tristate "Intel I810"
 	# !PREEMPT because of missing ioctl locking

drivers/staging/Kconfig

@@ -66,8 +66,6 @@ source "drivers/staging/phison/Kconfig"
 
 source "drivers/staging/line6/Kconfig"
 
-source "drivers/gpu/drm/nouveau/Kconfig"
-
 source "drivers/staging/octeon/Kconfig"
 
 source "drivers/staging/serqt_usb2/Kconfig"