fpu: Pass float_status to floatx80_invalid_encoding()

fpu: Pass float_status to floatx80_invalid_encoding()

The definition of which floatx80 encodings are invalid is
target-specific.  Currently we handle this with an ifdef, but we
would like to defer this decision to runtime.  In preparation, pass a
float_status argument to floatx80_invalid_encoding().

We will change the implementation from ifdef to looking at
the status argument in the following commit.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250224111524.1101196-7-peter.maydell@linaro.org