memory: samsung: exynos-srom: Fix of_iomap leak in exynos_srom_probe

memory: samsung: exynos-srom: Fix of_iomap leak in exynos_srom_probe

The of_platform_populate() call at the end of the function has a
possible failure path, causing a resource leak.

Replace of_iomap() with devm_platform_ioremap_resource() to ensure
automatic cleanup of srom->reg_base.

This issue was detected by smatch static analysis:
drivers/memory/samsung/exynos-srom.c:155 exynos_srom_probe()warn:
'srom->reg_base' from of_iomap() not released on lines: 155.

Fixes: 8ac2266d8831 ("memory: samsung: exynos-srom: Add support for bank configuration")
Cc: stable@vger.kernel.org
Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
Link: https://lore.kernel.org/r/20250806025538.306593-1-zhen.ni@easystack.cn
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>