target/m68k: Don't pass NULL float_status to floatx80_default_nan()

target/m68k: Don't pass NULL float_status to floatx80_default_nan()

Currently m68k_cpu_reset_hold() calls floatx80_default_nan(NULL)
to get the NaN bit pattern to reset the FPU registers. This
works because it happens that our implementation of
floatx80_default_nan() doesn't actually look at the float_status
pointer except for TARGET_MIPS. However, this isn't guaranteed,
and to be able to remove the ifdef in floatx80_default_nan()
we're going to need a real float_status here.

Rearrange m68k_cpu_reset_hold() so that we initialize env->fp_status
earlier, and thus can pass it to floatx80_default_nan().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241202131347.498124-28-peter.maydell@linaro.org