soc: mediatek: cmdq: change the type of input parameter

According to the cmdq hardware design, the subsys is u8,
the offset is u16 and the event id is u16.
This patch changes the type of subsys, offset and event id
to the correct type.

Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>