Fix loss of precision warning in signalmonitor.cpp.

Casting from a pointer to a "long" is only valid if they contain the
same number of bits.  Instead use the uintptr_t type, which is an
integer type that is guaranteed to have the same number of bits as a
pointer.

mythtv/libs/libmythtv/recorders/signalmonitor.cpp

@@ -217,7 +217,7 @@ SignalMonitor *SignalMonitor::Init(const QString& cardtype, int db_cardnum,
     {
         LOG(VB_GENERAL, LOG_ERR,
             QString("Failed to create signal monitor in Init(%1, %2, 0x%3)")
-                .arg(cardtype).arg(db_cardnum).arg((long)channel,0,16));
+                .arg(cardtype).arg(db_cardnum).arg((uintptr_t)channel,0,16));
     }
 
     return signalMonitor;