uboot-phytec

ARM: uniphier: make dram_init() independent of SG_MEMCONF

Currently, dram_init() code relies on the fact the DRAM size
configuration exists in the SG_MEMCONF register.

This will no longer be true for a planned new SoC, which will
replace SG_MEMCONF with a different register.

Refactor the hook in a more generic way.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>