nouveau: remove a few function stubs

nouveau_dmem_migrate_vma and nouveau_dmem_convert_pfn are only called
when CONFIG_DRM_NOUVEAU_SVM is enabled, so there is no need to provide
!CONFIG_DRM_NOUVEAU_SVM stubs for them.

Link: https://lore.kernel.org/r/20190814075928.23766-6-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/gpu/drm/nouveau/nouveau_dmem.h

@@ -45,16 +45,5 @@ static inline void nouveau_dmem_init(struct nouveau_drm *drm) {}
 static inline void nouveau_dmem_fini(struct nouveau_drm *drm) {}
 static inline void nouveau_dmem_suspend(struct nouveau_drm *drm) {}
 static inline void nouveau_dmem_resume(struct nouveau_drm *drm) {}
-
-static inline int nouveau_dmem_migrate_vma(struct nouveau_drm *drm,
-					   struct vm_area_struct *vma,
-					   unsigned long start,
-					   unsigned long end)
-{
-	return 0;
-}
-
-static inline void nouveau_dmem_convert_pfn(struct nouveau_drm *drm,
-					    struct hmm_range *range) {}
 #endif /* IS_ENABLED(CONFIG_DRM_NOUVEAU_SVM) */
 #endif