transport: Pass arbitrary kwargs to base-class constructor

Change-Id: I3cd5ba87cf53409ea97196d5789ed28eef072c68
diff --git a/pySim/transport/modem_atcmd.py b/pySim/transport/modem_atcmd.py
index f5a0f23..ecf463c 100644
--- a/pySim/transport/modem_atcmd.py
+++ b/pySim/transport/modem_atcmd.py
@@ -29,7 +29,8 @@
 
 class ModemATCommandLink(LinkBase):
 	"""Transport Link for 3GPP TS 27.007 compliant modems."""
-	def __init__(self, device:str='/dev/ttyUSB0', baudrate:int=115200):
+	def __init__(self, device:str='/dev/ttyUSB0', baudrate:int=115200, **kwargs):
+		super().__init__(**kwargs)
 		self._sl = serial.Serial(device, baudrate, timeout=5)
 		self._device = device
 		self._atr = None