ACPICA: Clib: Cleanup va_arg related code

ACPICA: Clib: Cleanup va_arg related code

ACPICA commit 32701b33cdc48d9bc43da8c9274cf172135b68fc

We in fact always use the compiler specific stdarg.h for GCC even
when ACPI_USE_STANDARD_HEADERS is not defined. So that the va_arg usages
can always be correct for different compiler options.

Likewise, the va_arg implemented in acenv.h is actually MSVC specific,
this patch also moves it to acmsvc.h and tunes acwin.h to correctly use
it.

After cleaning up, this patch removes all <stdarg.h> inclusions from
other files, but doesn't touch the BSD headers. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/32701b33
Link: https://bugs.acpica.org/show_bug.cgi?id=1298
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>