aarch64: Update fp8 dependencies

aarch64: Update fp8 dependencies

We agreed with LLVM developers to not enforce the architectural
dependencies between fp8 multiplication features, and they have already
been removed from LLVM and Binutils.  Remove them from GCC as well.

gcc/ChangeLog:

	* config/aarch64/aarch64-option-extensions.def
	(SSVE_FP8FMA): Adjust formatting.
	(FP8DOT4): Replace FP8FMA dependency with FP8.
	(SSVE_FP8DOT4): Replace SSVE_FP8FMA dependency with SME2+FP8.
	(FP8DOT2): Replace FP8DOT4 dependency with FP8.
	(SSVE_FP8DOT2): Replace SSVE_FP8DOT4 dependency with SME2+FP8.

gcc/testsuite/ChangeLog:

	* gcc.target/aarch64/pragma_cpp_predefs_4.c: Adjust expected
	defines.
	* gcc.target/aarch64/simd/vmla_lane_indices_1.c: Modify target
	pragmas.
	* gcc.target/aarch64/sve/acle/general-c/ternary_mfloat8_1.c:
	Ditto.
	* gcc.target/aarch64/sve/acle/general-c/ternary_mfloat8_lane_group_selection_1.c:
	Ditto.
	* gcc.target/aarch64/sve2/acle/asm/dot_lane_mf8.c: Ditto.
	* gcc.target/aarch64/sve2/acle/asm/dot_mf8.c: Ditto.