sys: timeutil: check for 32-bit time_t to avoid warning

A warning was propogated to error when building for
native_sim/native.

```
timeutil.h:519:17: error: result of comparison of constant \
  -9223372036854775808 with expression of type '__time_t' (aka 'long') \
  is always false [-Werror,-Wtautological-constant-out-of-range-compare]
```

This is due to the issue described in #90029.

Add workarounds for `timespec_to_timeout()` and `timespec_negate()`
until 90029 is resolved.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>