driver: ddr: imx: skip ddr_ss_gpr config on imx8mn

There is no DDR_SS_GPR0 exits on i.MX8MN, so skip setting
this register on i.MX8MN.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
1 file changed