memory: samsung: exynos-srom: Fix wrong count of registers

This patch fixes wrong count of array for SROM registers from probe
function.

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>