video: clps711x: Fix sparse warnings

This patch fixes below warning:

drivers/video/fbdev/clps711x-fb.c:314:17: warning: incorrect type in initializer (different address spaces)
drivers/video/fbdev/clps711x-fb.c:314:17: expected void *__p
drivers/video/fbdev/clps711x-fb.c:314:17: got char [noderef] <asn:2>*screen_base

Reported-by: kbuild test robot <[e-mail]>
Signed-off-by: Alexander Shiyan <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/video/fbdev/clps711x-fb.c

···
 		/* Setup start FB address */
 		writeb(info->fix.smem_start >> 28, cfb->base + CLPS711X_FBADDR);
 		/* Clean FB memory */
-		memset(info->screen_base, 0, cfb->buffsize);
+		memset_io(info->screen_base, 0, cfb->buffsize);
 	}
 
 	cfb->lcd_pwr = devm_regulator_get(dev, "lcd");