check for duplicated stack addresses by JimLee168

Based on https://code.google.com/p/jpcsp/source/detail?r=3569

Fix WWE SmackDown! vs. RAW 2006,2007,2008 booting
Fix #6671

2006 Modify log: https://gist.github.com/sum2012/a74a7199dcb3058fa5d8
Should not be a problem.  To test, you can temporarily change this to a u32_be.  On little endian (Intel) you will have the same problems comparing u32_be == u32 as someone on big endian will have comparing u32_le == u32.

-[Unknown]