changes to keyword specs

[Doug Evans <dje at sebabeach dot org>]

The relationship between enums and keywords is confusing.
I checked in this patch to help clear things up.

I'll update the src/cpu descriptions within a few days.

	* hardware.scm (<keyword>): Rename member print-name -> enum-prefix.
	Rename member prefix -> name-prefix.
	(<keyword> getters): Update.
	(-keyword-parse): Update.  Default enum-prefix to NAME-.
	(-keyword-read): Update.  Don't compute default value for
	enum-prefix here.
	(define-keyword): Update.
	(-hw-parse-keyword): Pass "UNUSED" for enum-prefix to -keyword-parse.
	* read.scm (cgen-rtl-version): New function.
	(-supported-rtl-versions): Add (0 8).
	* desc-cpu.scm (-gen-hw-decl): Remove cruft.
	* desc.scm (<keyword> gen-defn): prefix -> name-prefix.
	* gas-test.scm (<keyword> test-data): prefix -> name-prefix.
	* cpu/arm.cpu (gr-names, shift-type): Call define-rtl-version.
	Update, print-name -> enum-prefix, make uppercase.
	Remove unnecessary name-prefix spec.
	* cpu/fr30.cpu (gr-names, cr-names, dr-names): Ditto.
	* cpu/ip2k.cpu (register-names): Ditto.
	* cpu/m68k.cpu (dr-names, ar-names): Ditto.
	* cpu/sparc.cpu (gr-names): Ditto.
	* cpu/xc16x.cpu (gr-names, ext-names,psw-names): Ditto.
	(grb-names, conditioncode-names, extconditioncode-names): Ditto.
	(grb8-names, r8-names, regmem8-names, regdiv8-names): Ditto.
	(reg0-name, reg0-name1, regbmem8-names, memgr8-names): Ditto.
	* cpu/ia32.cpu (gr8-names, gr16-names, gr-names): Call
	define-rtl-version.  Update, print-name -> enum-prefix, make uppercase,
	prefix -> name-prefix.
	* cpu/sh64-compact.cpu (frc-names): Call define-rtl-version.
	Update, print-name -> enum-prefix, make uppercase.
	(drc-names, xf-names): Ditto.
	* cpu/xstormy16.cpu (gr-names, gr-Rb-names): Ditto.
	* doc/rtl.texi (Keywords): New section.
	(hardware indices): Update text.
	(rtl versions): Add 0.8.