ARM: EXYNOS: Add IO mapping for non-secure SYSRAM.

On TrustZone-enabled boards the non-secure SYSRAM is used for secondary
CPU bring-up, so add a mapping for it.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>