ACPI: ipmi: remove useless return statement for void function

Remove useless return statement for void function, reported by
checkpatch.pl.

WARNING: void function return statements are not generally useful
FILE: drivers/acpi/acpi_ipmi.c:482:
+       return;
+}
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_ipmi.c

@@ -478,7 +478,6 @@ static void ipmi_register_bmc(int iface, struct device *dev)
 	ipmi_dev_release(ipmi_device);
 err_ref:
 	put_device(smi_data.dev);
-	return;
 }
 
 static void ipmi_bmc_gone(int iface)