gcc/
	* config/nds32/constraints.md: Provide more constraints.
	* config/nds32/nds32.h (enum reg_class, REG_CLASS_NAMES,
	REG_CLASS_CONTENTS): Define R5_REG, R8_REG, and FRAME_POINTER_REG to
	support constraints usage.

Co-Authored-By: Kito Cheng <kito.cheng@gmail.com>

From-SVN: r254800