Initialize status in the axis poll method, which doesn't currently qu…

…ery the controller.

Without this change the following error is printed every time a status update is forced after a field is changed:

epics> 2021/11/02 16:37:36.321 asynMotorController:writeInt32 error, status=-222962768 axis=0, function=26, value=0

These errors were easy to reproduce by toggling the CNEN field or changing a limit.

acsMotionApp/src/SPiiPlusDriver.cpp

@@ -857,7 +857,7 @@ SPiiPlusAxis::SPiiPlusAxis(SPiiPlusController *pC, int axisNo)
 
 asynStatus SPiiPlusAxis::poll(bool* moving)
 {
-	asynStatus status;
+	asynStatus status = asynSuccess;
 	SPiiPlusController* controller = (SPiiPlusController*) pC_;
 	//static const char *functionName = "poll";
 	std::stringstream cmd;