soc: samsung: exynos-chipid: Add NULL pointer check in exynos_chipid_probe()

soc_dev_attr->revision could be NULL, thus,
a pointer check is added to prevent potential NULL pointer dereference.
This is similar to the fix in commit 3027e7b
("ice: Fix some null pointer dereference issues in ice_ptp.c").

This issue is found by our static analysis tool.

Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Link: https://lore.kernel.org/r/20250212213518.69432-1-chenyuan0y@gmail.com
Fixes: 3253b7b ("soc: samsung: Add exynos chipid driver support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Author: WhiteFox-Project

drivers/soc/samsung/exynos-chipid.c

@@ -134,6 +134,8 @@ static int exynos_chipid_probe(struct platform_device *pdev)
 
 	soc_dev_attr->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL,
 						"%x", soc_info.revision);
+	if (!soc_dev_attr->revision)
+		return -ENOMEM;
 	soc_dev_attr->soc_id = product_id_to_soc_id(soc_info.product_id);
 	if (!soc_dev_attr->soc_id) {
 		pr_err("Unknown SoC\n");