OMAP4: fix return value of omap4_l3_init

Don't PTR_ERR() a non-error pointer:

 initcall omap4_l3_init+0x0/0xdc returned -544980480 after 0 usecs
 initcall omap4_l3_init+0x0/0xdc returned with error code -544980480

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/devices.c

@@ -97,7 +97,7 @@ static int __init omap4_l3_init(void)
 
 	WARN(IS_ERR(od), "could not build omap_device for %s\n", oh_name);
 
-	return PTR_ERR(od);
+	return IS_ERR(od) ? PTR_ERR(od) : 0;
 }
 postcore_initcall(omap4_l3_init);