PATCH RFA: Use clz for MIPS ffs

[Eric Christopher]

> patch with a MIPS simulator using -mips32.  OK for mainline?
> 
> Ian
> 
> 
> 2005-07-13  Ian Lance Taylor  <ian@airs.com>
> 
> 	* config/mips/mips.h (CLZ_DEFINED_VALUE_AT_ZERO): Define.
> 
OK.

-eric