drm/exynos: cleanup exynos_drm_fbdev_update()

It can get exynos_gem object via function argument, so no need to call
exynos_drm_fb_gem_obj() in exynos_drm_fbdev_update.

It also can get struct drm_framebuffer *fb via helper->fb, so can remove
a function argument for it.
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fbdev.c

@@ -76,10 +76,10 @@ static struct fb_ops exynos_drm_fb_ops = {
 
 static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
 				   struct drm_fb_helper_surface_size *sizes,
-				     struct drm_framebuffer *fb)
+				   struct exynos_drm_gem_obj *obj)
 {
 	struct fb_info *fbi = helper->fbdev;
-	struct exynos_drm_gem_obj *obj;
+	struct drm_framebuffer *fb = helper->fb;
 	unsigned int size = fb->width * fb->height * (fb->bits_per_pixel >> 3);
 	unsigned int nr_pages;
 	unsigned long offset;
@@ -87,13 +87,6 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
 	drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
 	drm_fb_helper_fill_var(fbi, helper, sizes->fb_width, sizes->fb_height);
 
-	/* RGB formats use only one buffer */
-	obj = exynos_drm_fb_gem_obj(fb, 0);
-	if (!obj) {
-		DRM_DEBUG_KMS("gem object is null.\n");
-		return -EFAULT;
-	}
-
 	nr_pages = obj->size >> PAGE_SHIFT;
 
 	obj->kvaddr = (void __iomem *) vmap(obj->pages, nr_pages, VM_MAP,
@@ -175,7 +168,7 @@ static int exynos_drm_fbdev_create(struct drm_fb_helper *helper,
 	fbi->flags = FBINFO_FLAG_DEFAULT;
 	fbi->fbops = &exynos_drm_fb_ops;
 
-	ret = exynos_drm_fbdev_update(helper, sizes, helper->fb);
+	ret = exynos_drm_fbdev_update(helper, sizes, obj);
 	if (ret < 0)
 		goto err_destroy_framebuffer;