[NDS32] In nds32_valid_stack_push_pop_p(), we look into OP rtx to see if we indeed save $fp/$gp/$lp registers.

	* config/nds32/nds32-predicates.c
	(nds32_valid_stack_push_pop): Rename to ...
	(nds32_valid_stack_push_pop_p): ... this.
	* config/nds32/nds32-protos.h: Likewise.
	* config/nds32/predicates.md: Likewise.

From-SVN: r214853