trx_toolkit/fake_trx.py: avoid using TRXList.__getitem__()

Running with cProfile shows that there are quite a lot calls:

  469896    0.254    0.000    0.254    0.000 trx_list.py:37(__getitem__)

Let's better avoid using it in performance critical parts.

Change-Id: I2bbc0a2af8218af0b9a02d8e16d4216cf602892a

src/target/trx_toolkit/fake_trx.py

@@ -411,7 +411,7 @@ class Application(ApplicationBase):
 				self.append_child_trx(addr, port, idx, name)
 
 		# Burst forwarding between transceivers
-		self.burst_fwd = BurstForwarder(self.trx_list)
+		self.burst_fwd = BurstForwarder(self.trx_list.trx_list)
 
 		log.info("Init complete")
 
@@ -444,7 +444,7 @@ class Application(ApplicationBase):
 	def run(self):
 		# Compose list of to be monitored sockets
 		sock_list = []
-		for trx in self.trx_list:
+		for trx in self.trx_list.trx_list:
 			sock_list.append(trx.ctrl_if.sock)
 			sock_list.append(trx.data_if.sock)
 
@@ -454,7 +454,7 @@ class Application(ApplicationBase):
 			r_event, _, _ = select.select(sock_list, [], [])
 
 			# Iterate over all transceivers
-			for trx in self.trx_list:
+			for trx in self.trx_list.trx_list:
 				# DATA interface
 				if trx.data_if.sock in r_event:
 					msg = trx.recv_data_msg()

src/target/trx_toolkit/trx_list.py

@@ -34,6 +34,7 @@ class TRXList:
 	def __init__(self, trx_list = None):
 		self.trx_list = trx_list or []
 
+	# NOTE: do not use this in performance critical parts
 	def __getitem__(self, i):
 		return self.trx_list[i]