video: fbdev: sh_mobile_lcdcfb: fix sparse warnings about using incorrect types

Use ->screen_buffer instead of ->screen_base to fix sparse warnings.

[ Please see commit 17a7b0b4 ("fb.h: Provide alternate screen_base
  pointer") for details. ]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patchwork.freedesktop.org/patch/msgid/c687dbc5-cf5a-9508-2a61-e757a1a14568@samsung.com

drivers/video/fbdev/sh_mobile_lcdcfb.c

@@ -1572,7 +1572,7 @@ sh_mobile_lcdc_overlay_fb_init(struct sh_mobile_lcdc_overlay *ovl)
 	info->flags = FBINFO_FLAG_DEFAULT;
 	info->fbops = &sh_mobile_lcdc_overlay_ops;
 	info->device = priv->dev;
-	info->screen_base = ovl->fb_mem;
+	info->screen_buffer = ovl->fb_mem;
 	info->par = ovl;
 
 	/* Initialize fixed screen information. Restrict pan to 2 lines steps
@@ -2056,7 +2056,7 @@ sh_mobile_lcdc_channel_fb_init(struct sh_mobile_lcdc_chan *ch,
 	info->flags = FBINFO_FLAG_DEFAULT;
 	info->fbops = &sh_mobile_lcdc_ops;
 	info->device = priv->dev;
-	info->screen_base = ch->fb_mem;
+	info->screen_buffer = ch->fb_mem;
 	info->pseudo_palette = &ch->pseudo_palette;
 	info->par = ch;