target/m68k: Initialize float_status fields in gdb set/get functions

target/m68k: Initialize float_status fields in gdb set/get functions

In cf_fpu_gdb_get_reg() and cf_fpu_gdb_set_reg() we use a temporary
float_status variable to pass to floatx80_to_float64() and
float64_to_floatx80(), but we don't initialize it, meaning that those
functions could access uninitialized data.  Zero-init the structs.

(We don't need to set a NaN-propagation rule here because we
don't use these with a 2-argument fpu operation.)

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: 20241025141254.2141506-11-peter.maydell@linaro.org