ARM: ux500: fix ureachable iounmap()

The code was executing a return with a pointer before reaching
iounmap().
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-ux500/cpu-db8500.c

@@ -76,17 +76,19 @@ static struct arm_pmu_platdata db8500_pmu_platdata = {
 static const char *db8500_read_soc_id(void)
 {
 	void __iomem *uid;
+	const char *retstr;
 
 	uid = ioremap(U8500_BB_UID_BASE, 0x20);
 	if (!uid)
 		return NULL;
 	/* Throw these device-specific numbers into the entropy pool */
 	add_device_randomness(uid, 0x14);
-	return kasprintf(GFP_KERNEL, "%08x%08x%08x%08x%08x",
+	retstr = kasprintf(GFP_KERNEL, "%08x%08x%08x%08x%08x",
 			 readl((u32 *)uid+0),
 			 readl((u32 *)uid+1), readl((u32 *)uid+2),
 			 readl((u32 *)uid+3), readl((u32 *)uid+4));
 	iounmap(uid);
+	return retstr;
 }
 
 static struct device * __init db8500_soc_device_init(void)