rs6000: Remove wp and wq

rs6000: Remove wp and wq

wp becomes wa with isa p9tf, and wq is replaced by wa with isa p9kf.
To manage to do that, there is the new mode attribute VSisa.

	* config/rs6000/constraints.md (define_register_constraint "wp"):
	Delete.
	(define_register_constraint "wq"): Delete.
	* config/rs6000/rs6000.c (rs6000_debug_reg_global): Adjust.
	(rs6000_init_hard_regno_mode_ok): Adjust.
	* config/rs6000/rs6000.h (enum r6000_reg_class_enum): Delete
	RS6000_CONSTRAINT_wp and RS6000_CONSTRAINT_wq.
	* config/rs6000/vsx.md (define_mode_attr VSr3): Delete.
	(define_mode_attr VSa): Delete.
	(define_mode_attr VSisa): New.
	(rest of file): Adjust.
	* doc/md.texi (Machine Constraints): Adjust.

From-SVN: r271939