clk: mmp: pxa1908-apbc: Fix NULL vs IS_ERR() check

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

Fixes: 51ce559 ("clk: mmp: Add Marvell PXA1908 APBC driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/d7078eb7-a7d6-4753-b453-8fce15245c34@stanley.mountain
Acked-by: Duje Mihanović <duje.mihanovic@skole.hr>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: Dan Carpenter

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

@@ -96,8 +96,8 @@ static int pxa1908_apbc_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))