QGCSerialPortInfo: Add const in canFlash function

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

src/comm/QGCSerialPortInfo.cc

@@ -340,7 +340,7 @@ bool QGCSerialPortInfo::isSystemPort(QSerialPortInfo* port)
     return false;
 }
 
-bool QGCSerialPortInfo::canFlash(void)
+bool QGCSerialPortInfo::canFlash(void) const
 {
     BoardType_t boardType;
     QString     name;

src/comm/QGCSerialPortInfo.h

@@ -43,7 +43,7 @@ public:
     bool getBoardInfo(BoardType_t& boardType, QString& name) const;
 
     /// @return true: we can flash this board type
-    bool canFlash(void);
+    bool canFlash(void) const;
 
     /// @return true: Board is currently in bootloader
     bool isBootloader(void) const;