rs6000: wh -> d+p8v

rs6000: wh -> d+p8v

This replaces the "wh" constraint by "d", with isa "p8v".

	* config/rs6000/constraints.md (define_register_constraint "wh"):
	Delete.
	* config/rs6000/rs6000.h (enum r6000_reg_class_enum): Delete
	RS6000_CONSTRAINT_wh.
	* config/rs6000/rs6000.c (rs6000_debug_reg_global): Adjust.
	(rs6000_init_hard_regno_mode_ok): Adjust.
	* config/rs6000/rs6000.md: Replace "wh" constraint by "wa" with "p8v".
	* doc/md.texi (Machine Constraints): Adjust.

From-SVN: r271483