ACPI: SoC: APD: Check return value of acpi_dev_get_property()

`fch_misc_setup()` uses `acpi_dev_get_property()` to read the value of
"is-rv" passed in by BIOS in ACPI tables. However, not all BIOSes
might pass in this property and hence it is important to first check
the return value of `acpi_dev_get_property()` before referencing the
object filled by it.
Signed-off-by: NFurquan Shaikh <furquan@google.com>
[ rjw: Subject edits ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_apd.c

@@ -99,8 +99,8 @@ static int fch_misc_setup(struct apd_private_data *pdata)
 	if (ret < 0)
 		return -ENOENT;
 
-	acpi_dev_get_property(adev, "is-rv", ACPI_TYPE_INTEGER, &obj);
-	clk_data->is_rv = obj->integer.value;
+	if (!acpi_dev_get_property(adev, "is-rv", ACPI_TYPE_INTEGER, &obj))
+		clk_data->is_rv = obj->integer.value;
 
 	list_for_each_entry(rentry, &resource_list, node) {
 		clk_data->base = devm_ioremap(&adev->dev, rentry->res->start,