i386: Fix up handling of some -mno-avx512* options [PR123216]

i386: Fix up handling of some -mno-avx512* options [PR123216]

This PR is about -mavx10.2 -mno-avx512vl ICE on some builtin.
Though, because -mavx10.2 implies -mavx512vl (among many others), the
pattern is right and doesn't need to care about such weird cases.

What is wrong is the handling of -mno-avx512vl and various other options,
that should unset -mavx10.1 and that should unset -mavx10.2, but it doesn't.

I went through various ISAs which 10.1 or 10.2 implies, looking for the
ISA{,2}_*_SET and corresponding ISA{,2}_*_UNSET macros and their use or lack
thereof.
Here is what I found.
OPTION_MASK_ISA_AVX512FP16_UNSET has been incorrectly defined (avx512fp16
implies avx512bw, not the other way around), but fortunately wasn't used.
And then various ISAs implied by -mavx10.1 (except for -mavx512f which was
correct) missed clearing -mavx10.{1,2} on -mno-* handling.

As mentioned in the PR, it would be really nice to add some verification of
the set and unset macros to verify consistency.

2025-12-20  Jakub Jelinek  <jakub@redhat.com>

	PR target/123216
	* common/config/i386/i386-common.cc (OPTION_MASK_ISA_AVX512FP16_UNSET):
	Remove unused macro.
	(OPTION_MASK_ISA2_AVX512FP16_UNSET, OPTION_MASK_ISA2_AVX512BF16_UNSET,
	OPTION_MASK_ISA2_AVX512BW_UNSET): Or in OPTION_MASK_ISA2_AVX10_1_UNSET.
	(OPTION_MASK_ISA2_AVX512CD_UNSET, OPTION_MASK_ISA2_AVX512DQ_UNSET,
	OPTION_MASK_ISA2_AVX512VL_UNSET, OPTION_MASK_ISA2_AVX512IFMA_UNSET,
	OPTION_MASK_ISA2_AVX512VNNI_UNSET,
	OPTION_MASK_ISA2_AVX512VPOPCNTDQ_UNSET,
	OPTION_MASK_ISA2_AVX512VBMI_UNSET, OPTION_MASK_ISA2_AVX512VBMI2_UNSET,
	OPTION_MASK_ISA2_AVX512BITALG_UNSET): Define.
	(ix86_handle_option): For
	-mno-avx512{cd,dq,vl,ifma,vnni,vpopcntdq,vbmi,vbmi2,bitalg} also remove
	corresponding OPTION_MASK_ISA2_AVX512*_UNSET from ix86_isa_flags2
	and add it to ix86_isa_flags2_explicit.