rs6000: Disparage lfiwzx and similar

RA now chooses GEN_OR_VSX_REGS in most cases.  This is great in most
cases, but we often (or always?) use {l,st}{f,xs}iwzx now, which is
problematic because the integer load and store insns can use cheaper
addressing modes.  We can fix that by putting a small penalty on the
instruction alternatives for those.

2022-04-21  Segher Boessenkool  <segher@kernel.crashing.org>

	PR target/103197
	PR target/102146
	* config/rs6000/rs6000.md (zero_extendqi<mode>2 for EXTQI): Disparage
	the "Z" alternatives in {l,st}{f,xs}iwzx.
	(zero_extendhi<mode>2 for EXTHI): Ditto.
	(zero_extendsi<mode>2 for EXTSI): Ditto.
	(*movsi_internal1): Ditto.
	(*mov<mode>_internal1 for QHI): Ditto.
	(movsd_hardfloat): Ditto.