clk: mmp: Fix NULL vs IS_ERR() check

The devm_kzalloc() function returns NULL on error, not error pointers.
Fix the check.

Fixes: 03437e8 ("clk: mmp: Add Marvell PXA1908 APMU driver")
Signed-off-by: Charles Han <hanchunchao@inspur.com>
Link: https://lore.kernel.org/r/20250307064708.209511-1-hanchunchao@inspur.com
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: Charles Han

drivers/clk/mmp/clk-pxa1908-apmu.c

@@ -87,8 +87,8 @@ static int pxa1908_apmu_probe(struct platform_device *pdev)
 	struct pxa1908_clk_unit *pxa_unit;
 
 	pxa_unit = devm_kzalloc(&pdev->dev, sizeof(*pxa_unit), GFP_KERNEL);
-	if (IS_ERR(pxa_unit))
-		return PTR_ERR(pxa_unit);
+	if (!pxa_unit)
+		return -ENOMEM;
 
 	pxa_unit->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pxa_unit->base))