HwmonTempSensor: Add PollRate attribute

Tested:
1. Add the following configuration for test case:
   {
      "Address": "0x5c",
      "Bus": "47",
      "Name": "inlet",
      "PollRate": 100.0,
      "Thresholds": [
         ...
      ],
      "Type": "MAX31725"
   },
   - update sensor once every 100 seconds and verify pass.
2. Add "PollRate" in configuration for positive and negative value and
   verify pass.

Signed-off-by: Jeff Lin <JeffLin2@quantatw.com>
Change-Id: Ieeee2dd7ab6b3b2d237496b356e29b856078eb06
diff --git a/include/HwmonTempSensor.hpp b/include/HwmonTempSensor.hpp
index 3064c53..5cf0da5 100644
--- a/include/HwmonTempSensor.hpp
+++ b/include/HwmonTempSensor.hpp
@@ -19,6 +19,7 @@
                     std::shared_ptr<sdbusplus::asio::connection>& conn,
                     boost::asio::io_service& io, const std::string& fanName,
                     std::vector<thresholds::Threshold>&& thresholds,
+                    const float pollRate,
                     const std::string& sensorConfiguration,
                     const PowerState powerState);
     ~HwmonTempSensor();
@@ -31,6 +32,7 @@
     boost::asio::streambuf readBuf;
     std::string path;
     size_t errCount;
+    unsigned int sensorPollMs;
 
     void handleResponse(const boost::system::error_code& err);
     void checkThresholds(void) override;