ddr: imx: Add new rates for i.MX91

iMX91 reuses iMX93 controller and PHY, but with lower speed,
so add new DDR rates for i.MX91.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
1 file changed