fpu: Always decide snan_bit_is_one() at runtime

fpu: Always decide snan_bit_is_one() at runtime

Currently we have a compile-time shortcut where we return a hardcode
value from snan_bit_is_one() on everything except MIPS, because we
know that's the only target that needs to change
status->no_signaling_nans at runtime.

Remove the ifdef, so we always look at the status flag.  This means
we must update the two targets (HPPA and SH4) that were previously
hardcoded to return true so that they set the status flag correctly.

This has no behavioural change, but will be necessary if we want to
build softfloat once for all targets.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250224111524.1101196-11-peter.maydell@linaro.org
Message-id: 20250217125055.160887-9-peter.maydell@linaro.org