fbmem: return -EFAULT on copy_to_user() failure

copy_to_user() returns the number of bytes remaining to be copied.
put_user() returns -EFAULT on error.

This function ORs a bunch of stuff together and returns jumbled non-zero
values on error.  It should return -EFAULT.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/fbmem.c

@@ -1305,7 +1305,9 @@ static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
 	err |= copy_to_user(fix32->reserved, fix->reserved,
 			    sizeof(fix->reserved));
 
-	return err;
+	if (err)
+		return -EFAULT;
+	return 0;
 }
 
 static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,