Add several new files for preparation of providing modules

Add several new files for preparation of providing modules
that are going to be separated from nds32.c source.

gcc/
	* config.gcc (nds32*): Add new modules to extra_objs.
	(nds32le-*-*): Use t-nds32 makefile fragment for new modules.
	(nds32be-*-*): Likewise.
	* config/nds32/nds32-cost.c: New file.
	* config/nds32/nds32-fp-as-gp.c: New file.
	* config/nds32/nds32-intrinsic.c: New file.
	* config/nds32/nds32-isr.c: New file.
	* config/nds32/nds32-md-auxiliary.c: New file.
	* config/nds32/nds32-memory-manipulation.c: New file.
	* config/nds32/nds32-pipelines-auxiliary.c: New file.
	* config/nds32/nds32-predicates.c: New file.
	* config/nds32/t-nds32: New file.

Co-Authored-By: Kito Cheng <kito@0xlab.org>
Co-Authored-By: Monk Chiang <sh.chiang04@gmail.com>
From-SVN: r212280