Convert system manager for Gen5, Arria 10 and Stratix 10 from struct
to defines.

Change to get system manager base address from DT node instead of
using #define.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>