hw/arm/collie: Create the RAM in the board

hw/arm/collie: Create the RAM in the board

The SDRAM is incorrectly created in the SA1110 SoC.
Move its creation in the board code, this will later allow the
board to have the QOM ownership of the RAM.

Reviewed-by: Richard Henderson <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Alistair Francis <[email protected]>
Message-id: 20191021190653[email protected]
Signed-off-by: Peter Maydell <[email protected]>