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

[Cary Coutant]

-    this->is_n64_ = elfcpp::abi_64(ehdr.get_e_ident()[elfcpp::EI_CLASS]);
+    this->is_n64_ = size == 64;

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