ddr: imx9: Add workaround for DDRPHY rank-to-rank errata

ddr: imx9: Add workaround for DDRPHY rank-to-rank errata

According to DDRPHY errata, the Rank-to-Rank Spacing and tphy_rdcsgap
specification does not include the Critical Delay Difference (CDD) to
properly define the required rank-to-rank read command spacing after
executing PHY training firmware.

Following the errata workaround, at the end of data training, we get
all CDD values through the MessageBlock, then re-configure the DDRC
timing of WWT/WRT/RRT/RWT with comparing MAX CDD values.

Signed-off-by: Ye Li <ye.li@nxp.com>
Acked-by: Peng Fan <peng.fan@nxp.com>