[U-Boot] [PATCH v4 0/7] mx23: Make DDR initialization stable

Prior to this series running 'memtester' utility in Linux on a mx23evk always resulted in many errors during stress testing, if the kernel is loaded via U-boot.

Running the same test and loading the kernel via FSL bootlets resulted on zero errors.

Adjust U-boot so that it can also pass the 'memtester' stress test.

After this series was applied, no more DDR errors were observed on a mx23evk.