Set size of callback irq array to IrqCnt

Rather than hard coding the size of the callback array for irqs,
instead set the size to IrqCnt which is defined by the irq enumeration.

Author: c1728p9

hal/api/CAN.h

@@ -203,7 +203,9 @@ class CAN {
         EpIrq,
         AlIrq,
         BeIrq,
-        IdIrq
+        IdIrq,
+
+        IrqCnt
     };
 
     /** Attach a function to call whenever a CAN frame received interrupt is
@@ -246,7 +248,7 @@ class CAN {
     virtual void lock();
     virtual void unlock();
     can_t               _can;
-    Callback<void()>    _irq[9];
+    Callback<void()>    _irq[IrqCnt];
     PlatformMutex       _mutex;
 };
 

hal/api/SerialBase.h

@@ -55,7 +55,9 @@ class SerialBase {
 
     enum IrqType {
         RxIrq = 0,
-        TxIrq
+        TxIrq,
+
+        IrqCnt
     };
 
     enum Flow {
@@ -231,7 +233,7 @@ class SerialBase {
 #endif
 
     serial_t         _serial;
-    Callback<void()> _irq[2];
+    Callback<void()> _irq[IrqCnt];
     int              _baud;
 
 };