The imx_ddr_size() function may overflow as it is possible to kind of
over provision the DDR controller. Fix this by capping it to 2 GB which
is the maximum allowed size as per reference manual.
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>