uniphier: make on-chip SRAM region configurable
uniphier: make on-chip SRAM region configurable

The on-chip SRAM region will be changed in the next SoC. Make it
configurable. Also, split the mmap code into a new helper function
so that it can be re-used for another boot mode.

Change-Id: I89f40432bf852a58ebc9be5d9dec4136b8dc010b
Signed-off-by: Masahiro Yamada <378b411a8a63ecc7605ec4272234862d7781c6ae@socionext.com>

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware