include: types: Add __aligned(x) to define the minimum alignement

The __aligned(x) macro is a common wrapper around compiler's
aligned attribute, which allow to define the minimum alignement
of a data type. Let's add this macro.

Signed-off-by: Christoph Muellner <cmuellner@linux.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>