Bluetooth: btusb: Default CONFIG_BT_HCIBTUSB_POLL_SYNC=y

poll_sync has been proven to fix races of USB data and event endpoints
so this enables it by default.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Tedd Ho-Jeong An <tedd.an@intel.com>

drivers/bluetooth/Kconfig

@@ -48,6 +48,7 @@ config BT_HCIBTUSB_AUTOSUSPEND
 config BT_HCIBTUSB_POLL_SYNC
 	bool "Enable USB poll_sync for Bluetooth USB devices by default"
 	depends on BT_HCIBTUSB
+	default y
 	help
 	  poll_sync synchronizes the USB data and event endpoints by
 	  prioritizing the later.