drm/msm: change gem->vmap() to get/put

Before we can add vmap shrinking, we really need to know which vmap'ings
are currently being used.  So switch to get/put interface.  Stubbed put
fxns for now.

Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index a9223be..ffd4a33 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -158,7 +158,7 @@
 
 	dev->mode_config.fb_base = paddr;
 
-	fbi->screen_base = msm_gem_vaddr_locked(fbdev->bo);
+	fbi->screen_base = msm_gem_get_vaddr_locked(fbdev->bo);
 	if (IS_ERR(fbi->screen_base)) {
 		ret = PTR_ERR(fbi->screen_base);
 		goto fail_unlock;
@@ -251,6 +251,7 @@
 
 	/* this will free the backing object */
 	if (fbdev->fb) {
+		msm_gem_put_vaddr(fbdev->bo);
 		drm_framebuffer_unregister_private(fbdev->fb);
 		drm_framebuffer_remove(fbdev->fb);
 	}