drivers/video: Move dereference after NULL test

If the NULL test on fbi is needed, then the dereference should be after the
NULL test.

A simplified version of the semantic match that detects this problem is as
follows (http://coccinelle.lip6.fr/):

// <smpl>
@match exists@
expression x, E;
identifier fld;
@@

* x->fld
  ... when != \(x = E\|&x\)
* x == NULL
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/pxafb.c

@@ -1221,13 +1221,14 @@ static void setup_smart_timing(struct pxafb_info *fbi,
 static int pxafb_smart_thread(void *arg)
 {
 	struct pxafb_info *fbi = arg;
-	struct pxafb_mach_info *inf = fbi->dev->platform_data;
+	struct pxafb_mach_info *inf;
 
-	if (!fbi || !inf->smart_update) {
+	if (!fbi || !fbi->dev->platform_data->smart_update) {
 		pr_err("%s: not properly initialized, thread terminated\n",
 				__func__);
 		return -EINVAL;
 	}
+	inf = fbi->dev->platform_data;
 
 	pr_debug("%s(): task starting\n", __func__);