print zone failsafe reason when enter failsafe mode
Tested:
```
Jun 24 01:52:45 bmc sel-logger[640]: cpu0_nbm critical high threshold assert. Reading=49.000000 Threshold=45.000000.
Jun 24 01:52:46 bmc swampd[2944]: Zone 2 fans, entering failsafe mode, output pwm: 100
Jun 24 01:52:46 bmc swampd[2944]: Fail sensor: cpu0_nbm, reason: Sensor threshold asserted
Jun 24 01:52:46 bmc swampd[2944]: Zone 0 fans, entering failsafe mode, output pwm: 100
Jun 24 01:52:46 bmc swampd[2944]: Fail sensor: cpu0_nbm, reason: Sensor threshold asserted
```
Signed-off-by: Harvey Wu <Harvey.Wu@quantatw.com>
Change-Id: I607d01b6bed11b00a40153db6521a9c9d23da519
diff --git a/sensors/pluggable.hpp b/sensors/pluggable.hpp
index bd5bc1f..d139876 100644
--- a/sensors/pluggable.hpp
+++ b/sensors/pluggable.hpp
@@ -26,6 +26,7 @@
void write(double value) override;
void write(double value, bool force, int64_t* written) override;
bool getFailed(void) override;
+ std::string getFailReason(void) override;
private:
std::unique_ptr<ReadInterface> _reader;