support for Dram parametres on u-boot-misc

[jmsvigno]

@hexdump0815 is it possible to add support to Dram parameters like below the version of Das U-Boot" Source Tree and denx works but does not have the patches that you suggested in mainline readme.h616, my box tv need these parameters

CONFIG_DRAM_SUN50I_H616_DX_ODT=0x08080808 CONFIG_DRAM_SUN50I_H616_DX_DRI=0x0e0e0e0e CONFIG_DRAM_SUN50I_H616_CA_DRI=0x0e0e CONFIG_DRAM_SUN50I_H616_TPR10=0xf83438 CONFIG_MACH_SUN50I_H616=y CONFIG_SUNXI_DRAM_LPDDR3=y CONFIG_SUNXI_DRAM_H616_LPDDR3=y