PR106342 - IBM zSystems: Provide vsel for all vector modes

PR106342 - IBM zSystems: Provide vsel for all vector modes

dg.exp=pr104612.c fails with an ICE on s390x, because copysignv2sf3
produces an insn that vsel<mode> is supposed to recognize, but can't,
because it's not defined for V2SF.  Fix by defining it for all vector
modes supported by copysign<mode>3.

gcc/ChangeLog:

	* config/s390/vector.md (V_HW_FT): New iterator.
	* config/s390/vx-builtins.md (vsel<mode>): Use V_HW_FT instead
	of V_HW.

(cherry picked from commit 2f17f489de47d46626ed85804c3b810547ef550e)