Remove extra "channel" option to root parameters

Their corresponding channel numbers are already represented with their
"value" options.

pytec/pytec/gui/view/ctrl_panel.py

@@ -77,9 +77,6 @@ class CtrlPanel(QObject):
             for ch in range(self.NUM_CHANNELS)
         ]
 
-        for i, param in enumerate(self.params):
-            param.channel = i
-
         for i, tree in enumerate(self.trees_ui):
             tree.setHeaderHidden(True)
             tree.setParameters(self.params[i], showTop=False)

pytec/tec_qt.py

@@ -262,7 +262,7 @@ class MainWindow(QtWidgets.QMainWindow):
     @asyncSlot(object, object)
     async def send_command(self, param, changes):
         """Translates parameter tree changes into thermostat set_param calls"""
-        ch = param.channel
+        ch = param.value()
 
         for inner_param, change, data in changes:
             if change == "value":