ARM: EXYNOS: Fix the check for non-smp configuration

Commit 1754c42e

("ARM: exynos: move sysram info to exynos.c") missed
out the CONFIG_ prefix causing exynos_sysram_init() to get called twice
for SMP configurations.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Reviewed-by: Sachin Kamat <sachin.kamat@samsug.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>