omap: mailbox: 2420 should be detected at run-time

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>

arch/arm/mach-omap2/mailbox.c

@@ -455,7 +455,8 @@ err_dsp:
 static int __devexit omap2_mbox_remove(struct platform_device *pdev)
 {
 #if defined(CONFIG_ARCH_OMAP2420)
-	omap_mbox_unregister(&mbox_iva_info);
+	if (cpu_is_omap2420())
+		omap_mbox_unregister(&mbox_iva_info);
 #endif
 
 	if (cpu_is_omap44xx()) {