ARM: EXYNOS: Map SYSRAM through generic DT bindings

Instead of hardcoding the SYSRAM details for each SoC,
pass this information through device tree (DT) and make
the code SoC agnostic. Generic DT SRAM bindings are
used for achieving this.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>