rs6000: Delete many HAVE_AS_* (PR87149)

rs6000: Delete many HAVE_AS_* (PR87149)

This deletes most HAVE_AS_* that determine if the assembler supports
some ISA level (and also HAVE_AS_MFPGPR and HAVE_AS_DFP).

These are not useful: we will only generate an instruction that requires
some newer ISA if the user specifically asked for it (with -mcpu=, say).
If the assembler cannot handle that, it is fine if it gives an error.

They also hurt: it increases the number of possible situations that all
need handling and all need testing.  We do not handle all cases, and
obviously do not test all either.

This patch removes:

HAVE_AS_POPCNTB (power5,  2.02)
HAVE_AS_FPRND   (power5+, 2.04)
HAVE_AS_CMPB    (power6,  2.05)
HAVE_AS_POPCNTD (power7,  2.06)
HAVE_AS_POWER8  (power8,  2.07)
HAVE_AS_POWER9  (power9,  3.0)

HAVE_AS_DFP     (power6,  2.05, server)
HAVE_AS_MFPGPR  (power6x but not later, not arch)

	PR target/87149
	* config.in (HAVE_AS_CMPB, HAVE_AS_DFP, HAVE_AS_FPRND, HAVE_AS_MFPGPR,
	HAVE_AS_POPCNTB, HAVE_AS_POPCNTD, HAVE_AS_POWER8, HAVE_AS_POWER9):
	Delete, always treat as true.
	* config/powerpcspe/powerpcspe.c (rs6000_option_override_internal):
	Ditto.  Simplify remaining code.
	* config/powerpcspe/powerpcspe.h: Ditto.
	* config/rs6000/rs6000.c (rs6000_option_override_internal): Ditto.
	Simplify remaining code.
	(rs6000_expand_builtin): Ditto.
	* config/rs6000/rs6000.h: Ditto.
	* configure.ac: Ditto.
	* configure: Regenerate.

From-SVN: r264675