api: add C++ friendly version of Z_TIMEOUT_TICKS.

The designated initializer used in Z_TIMEOUT_TICKS causes problems for
some C++ parsers (at least in Eclipse).
Let's use standard C++ list initialization (C++11 and up) instead.
Designated initializatin is going to C++20,
so it is not neccessary to apply C++ specific code
for that version and up.

Signed-off-by: Artur Lipowski <Artur.Lipowski@hidglobal.com>