[PATCH] gold: Remove ei_class from mips.cc.

[Vladimir Radosavljevic]

> The only places left that use is_n64_ are is_n64() and is_newabi(),
> and is_n64() isn't ever called. You could remove this data member, the
> is_n64() method, and change is_newabi() to check for size == 64.
> 
> -cary

I've removed is_n64_ from Mips_relobj class in a new version of the patch. Method is_n64() is called from Mips_relobj::do_read_symbols,
and from Relocate::relocate, so I decided to keep it. I've also changed is_newabi() method to call is_n32() and is_n64() methods.

Regards,
Vladimir.