libstdc++: Always-inline most of non-cmath fixed_size implementation

For simd, the inlining behavior should be similar to builtin types. (No
operator on buitin types is ever translated into a function call.)
Therefore, always_inline is the right choice (i.e. inline on -O0 as
well).

Signed-off-by: Matthias Kretz <m.kretz@gsi.de>

libstdc++-v3/ChangeLog:

	PR libstdc++/108030
	* include/experimental/bits/simd_fixed_size.h
	(_SimdImplFixedSize::_S_broadcast): Replace inline with
	_GLIBCXX_SIMD_INTRINSIC.
	(_SimdImplFixedSize::_S_generate): Likewise.
	(_SimdImplFixedSize::_S_load): Likewise.
	(_SimdImplFixedSize::_S_masked_load): Likewise.
	(_SimdImplFixedSize::_S_store): Likewise.
	(_SimdImplFixedSize::_S_masked_store): Likewise.
	(_SimdImplFixedSize::_S_min): Likewise.
	(_SimdImplFixedSize::_S_max): Likewise.
	(_SimdImplFixedSize::_S_complement): Likewise.
	(_SimdImplFixedSize::_S_unary_minus): Likewise.
	(_SimdImplFixedSize::_S_plus): Likewise.
	(_SimdImplFixedSize::_S_minus): Likewise.
	(_SimdImplFixedSize::_S_multiplies): Likewise.
	(_SimdImplFixedSize::_S_divides): Likewise.
	(_SimdImplFixedSize::_S_modulus): Likewise.
	(_SimdImplFixedSize::_S_bit_and): Likewise.
	(_SimdImplFixedSize::_S_bit_or): Likewise.
	(_SimdImplFixedSize::_S_bit_xor): Likewise.
	(_SimdImplFixedSize::_S_bit_shift_left): Likewise.
	(_SimdImplFixedSize::_S_bit_shift_right): Likewise.
	(_SimdImplFixedSize::_S_remquo): Add inline keyword (to be
	explicit about not always-inline, yet).
	(_SimdImplFixedSize::_S_isinf): Likewise.
	(_SimdImplFixedSize::_S_isfinite): Likewise.
	(_SimdImplFixedSize::_S_isnan): Likewise.
	(_SimdImplFixedSize::_S_isnormal): Likewise.
	(_SimdImplFixedSize::_S_signbit): Likewise.