iasl: Remove date and time from -vd option, for reproducible build

[emaste]

Summary

iasl's use of __DATE__ and __TIME__ is one of two issues remaining preventing a reproducible build of FreeBSD world + kernel.

The build date and time is not particularly relevant, so just remove it (instead of pinning it to an arbitrary value, via e.g. SOURCE_DATE_EPOCH).

PR: 215421

[emaste]

sys/contrib/dev/acpica/compiler/asloptions.c

728–729

I argue that this is not useful information and we're better off just omitting the option, but if prefered we could either change it to "%s Build date/time: unknown\n", ASL_COMPILER_NAME, or hard-code an arbitrary date/time.

[emaste]

Leave -vd in place, just remove the nonreproducible date and time

[emaste]

@jkim committed rS311529