ddr: imx93: Add 625M bypass clock support

Add 625M bypass clock that may be used DRAM 625M
bypass mode support.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>