MLK-13539: mx6sl: evk: lpddr2: add pre charge command all

LPDDR2 script MX6SL_MMDC_LPDDR2_register_programming_aid_v0.9.inc

Updated to add Precharge all command per JEDEC
The memory controller may optionally issue a precharge-all command
prior to the MRW reset command
This is strongly recommended to ensure robust DRAM initialization

Signed-off-by: Adrian Alonso <adrian.alonso@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>