siox: driver init boilerplate reduction v3

[Enrico Weigelt, metux IT consult]

Hi folks,


this is v3 of my siox/gpio series from last week.

v3: fixed subject and formatting pointed out by Uwe,
    second patch (gpio-siox.c) already acked by him

v2: fixed the typos pointed out by Uwe.


--mtx