drm/exynos/fbdev: don't set mode_config.fb_base

AFAICT, the fb_base of a drm_device's mode_config is never used.  It isn't
accessed by core drm, it isn't used by fbmem, and it isn't exposed to user
space.

Furthermore, it is probably supposed to be a physical address, not the
dma address mapped to the display controller, so this is just wrong.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fbdev.c

@@ -121,7 +121,6 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
 	offset = fbi->var.xoffset * (fb->bits_per_pixel >> 3);
 	offset += fbi->var.yoffset * fb->pitches[0];
 
-	dev->mode_config.fb_base = (resource_size_t)buffer->dma_addr;
 	fbi->screen_base = buffer->kvaddr + offset;
 	fbi->screen_size = size;