arm: mach-k3: Move MSMC fixup to SoC level

The MSMC fixup is something we do based on SoC, not based on the board.
So this fixup does not belong in the board files. Move this to the
mach-k3 common file so that it does not have to be done in each board
that uses these SoCs.

We use ft_system_setup() here instead of ft_board_setup() since it is no
longer board level. Enable OF_SYSTEM_SETUP in the configurations that use
this to keep functionality the same.

Signed-off-by: Andrew Davis <afd@ti.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>