ARM: pxafb: Fix access to nonexistent member of pxafb_info

In case CONFIG_FB_PXA_OVERLAY is not defined, the pxafb_freq_transition()
function tests nonexistent member of pxafb_info (since the member is not
part of the structure).

Fix this by wraping the test in ifdef, even if I don't really like how the code
looks now. The check doesn't have to happen if overlays are disabled at all as
the check is always true then.
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Acked-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

drivers/video/pxafb.c

@@ -1648,7 +1648,9 @@ pxafb_freq_transition(struct notifier_block *nb, unsigned long val, void *data)
 
 	switch (val) {
 	case CPUFREQ_PRECHANGE:
-		if (!fbi->overlay[0].usage && !fbi->overlay[1].usage)
+#ifdef CONFIG_FB_PXA_OVERLAY
+		if (!(fbi->overlay[0].usage || fbi->overlay[1].usage))
+#endif
 			set_ctrlr_state(fbi, C_DISABLE_CLKCHANGE);
 		break;