Support for different IMX8MQ LPDDR4 configurations

1. Auto-detect DDR boot frequency and backup DRAM PLL cfg
2. Save/restore all necessary DDRC/DDRPHY register to adapt to all
   LPDDR4 configurations

Change-Id: I2d63fe9928e826a7d0072bd378621c38b12a2336
Signed-off-by: Michael Brooks <michaelbrooks@google.com>
6 files changed