spmi: pmic-arb: fix a possible null pointer dereference

If "core" memory resource is not specified, then the driver could
end up dereferencing a null pointer. Fix this issue.
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/spmi/spmi-pmic-arb.c

@@ -955,14 +955,14 @@ static int spmi_pmic_arb_probe(struct platform_device *pdev)
 	pmic_arb->spmic = ctrl;
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "core");
-	pmic_arb->core_size = resource_size(res);
-
 	core = devm_ioremap_resource(&ctrl->dev, res);
 	if (IS_ERR(core)) {
 		err = PTR_ERR(core);
 		goto err_put_ctrl;
 	}
 
+	pmic_arb->core_size = resource_size(res);
+
 	pmic_arb->ppid_to_apid = devm_kcalloc(&ctrl->dev, PMIC_ARB_MAX_PPID,
 					      sizeof(*pmic_arb->ppid_to_apid),
 					      GFP_KERNEL);