Bluetooth: hci_bcm: Make shutdown and device wake GPIO optional

According to the devicetree binding the shutdown and device wake
GPIOs are optional. Since commit 3e81a4ca51a1 ("Bluetooth: hci_bcm:
Mandate presence of shutdown and device wake GPIO") this driver
won't probe anymore on Raspberry Pi 3 and Zero W (no device wake GPIO
connected). So fix this regression by reverting this commit partially.

Fixes: 3e81a4ca51a1 ("Bluetooth: hci_bcm: Mandate presence of shutdown and device wake GPIO")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/hci_bcm.c

@@ -922,12 +922,13 @@ static int bcm_get_resources(struct bcm_device *dev)
 
 	dev->clk = devm_clk_get(dev->dev, NULL);
 
-	dev->device_wakeup = devm_gpiod_get(dev->dev, "device-wakeup",
-					    GPIOD_OUT_LOW);
+	dev->device_wakeup = devm_gpiod_get_optional(dev->dev, "device-wakeup",
+						     GPIOD_OUT_LOW);
 	if (IS_ERR(dev->device_wakeup))
 		return PTR_ERR(dev->device_wakeup);
 
-	dev->shutdown = devm_gpiod_get(dev->dev, "shutdown", GPIOD_OUT_LOW);
+	dev->shutdown = devm_gpiod_get_optional(dev->dev, "shutdown",
+						GPIOD_OUT_LOW);
 	if (IS_ERR(dev->shutdown))
 		return PTR_ERR(dev->shutdown);