configure.target: Fix comment for mips atomicity.

2002-07-08  Eric Christopher  <echristo@redhat.com>

	* configure.target: Fix comment for mips atomicity. Add
	mips*-*-linux* target, enable atomic operations there.
	* config/cpu/mips/atomicity.h: Fix comments, remove
	#ifndef/#endif. Add push/pop mips2.

From-SVN: r55331