Fix warnings for AVR

See PR [Fixed warnings from cppcheck (platformio) and -Wall arduino-cli](khoih-prog/TimerInterrupt#10)

Author: khoih-prog

src/AVRTimerInterrupt_Generic.h

@@ -203,21 +203,31 @@ class TimerInterrupt
 
   public:
 
-  TimerInterrupt() 
-  { 
-    _timer = -1; 
-    _frequency = 0; 
-    _callback = NULL; 
-    _params = NULL; 
-  };
-  
-  TimerInterrupt(uint8_t timerNo) 
-  { 
-    _timer = timerNo; 
-    _frequency = 0; 
-    _callback = NULL; 
-    _params = NULL; 
-  };
+  TimerInterrupt()
+    {
+      _timer              = -1;
+      _frequency          = 0;
+      _callback           = NULL;
+      _params             = NULL;
+      _timerDone          = false;
+      _prescalerIndex     = NO_PRESCALER;
+      _OCRValue           = 0;
+      _OCRValueRemaining  = 0;
+      _toggle_count       = -1;
+    };
+
+    explicit TimerInterrupt(uint8_t timerNo)
+    {
+      _timer              = timerNo;
+      _frequency          = 0;
+      _callback           = NULL;
+      _params             = NULL;
+      _timerDone          = false;
+      _prescalerIndex     = NO_PRESCALER;
+      _OCRValue           = 0;
+      _OCRValueRemaining  = 0;
+      _toggle_count       = -1;
+    };
 
   void callback() __attribute__((always_inline))
   {
@@ -892,7 +902,7 @@ class TimerInterrupt
     return _timer; 
   };
 
-  volatile long getCount() __attribute__((always_inline))
+  long getCount() __attribute__((always_inline))
   { 
     return _toggle_count;    
   };
@@ -908,12 +918,12 @@ class TimerInterrupt
     //interrupts();
   };
 
-  volatile long get_OCRValue() __attribute__((always_inline))
+  long get_OCRValue() __attribute__((always_inline))
   { 
     return _OCRValue;    
   };
 
-  volatile long get_OCRValueRemaining() __attribute__((always_inline))
+  long get_OCRValueRemaining() __attribute__((always_inline))
   { 
     return _OCRValueRemaining;    
   };
@@ -928,7 +938,7 @@ class TimerInterrupt
     else
       _OCRValueRemaining -= min(MAX_COUNT_8BIT, _OCRValueRemaining);      
 
-    if (_OCRValueRemaining <= 0)
+    if (_OCRValueRemaining == 0)
     {
        // Reset value for next cycle
       _OCRValueRemaining = _OCRValue;