hp_wireless: Inform the user if hp_wireless_input_setup()/add() fails

In hpwl_add() there is a unused variable err to which we assign the
result of hp_wireless_input_setup() but we don't do anything depending
on the result so print out a message that informs the user if add()
(hp_wireless_input_setup()) fails since acpi_device_probe() doesn't
print anything in this case.
Signed-off-by: NGiedrius Statkevicius <giedriuswork@gmail.com>
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>

drivers/platform/x86/hp-wireless.c

@@ -85,6 +85,9 @@ static int hpwl_add(struct acpi_device *device)
 	int err;
 
 	err = hp_wireless_input_setup();
+	if (err)
+		pr_err("Failed to setup hp wireless hotkeys\n");
+
 	return err;
 }