Serial links: Do not connect to known system peripherals

We were connecting to system peripherals before, which adds boot delay as QGC re-tries opening the port. We were also opening serial ports two times on Mac OS: Once as /dev/cu.usbmodem1 and once as /dev/tty.usbmodem1 - since the cu.usbmodem alias was already open, the 2nd opening always failed, leading to further boot delay.

src/comm/LinkManager.cc

@@ -501,6 +501,13 @@ void LinkManager::_updateAutoConnectLinks(void)
         QString boardName;
 
         if (portInfo.getBoardInfo(boardType, boardName)) {
+
+            if (portInfo.isSystemPort()) {
+                // Don't connect to system ports
+                qCDebug(LinkManagerLog) << "Not opening known system ports" << portInfo.systemLocation();
+                continue;
+            }
+
             if (portInfo.isBootloader()) {
                 // Don't connect to bootloader
                 qCDebug(LinkManagerLog) << "Waiting for bootloader to finish" << portInfo.systemLocation();

src/comm/QGCSerialPortInfo.cc

@@ -271,6 +271,27 @@ bool QGCSerialPortInfo::isBootloader(void) const
     }
 }
 
+bool QGCSerialPortInfo::isSystemPort(void) const
+{
+    // Known operating system peripherals that are NOT a drone
+
+    // These are known Mac OS ports that
+    // are never connected to a drone but instead
+    // to other system peripherals.
+    if (systemLocation().contains("tty.MALS")
+        || systemLocation().contains("tty.SOC")
+        || systemLocation().contains("tty.Bluetooth-Incoming-Port")
+        // We open these by their cu.usbserial and cu.usbmodem handles
+        // already. We don't want to open them twice and conflict
+        // with ourselves.
+        || systemLocation().contains("tty.usbserial")
+        || systemLocation().contains("tty.usbmodem")) {
+
+        return true;
+    }
+    return false;
+}
+
 bool QGCSerialPortInfo::canFlash(void)
 {
     BoardType_t boardType;

src/comm/QGCSerialPortInfo.h

@@ -49,6 +49,9 @@ public:
     /// @return true: Board is currently in bootloader
     bool isBootloader(void) const;
 
+    /// @return true: Port is a system port and not an autopilot
+    bool isSystemPort(void) const;
+
 private:
     typedef struct {
         const char* classString;