Handle EINVAL, ENOIOCTLCMD, ENOTTY and EPERM errors

According to TTY_IOCTL(4), the ioctl on tty device can return these
errors, which we need to interpret to QSP::SerialPortError.

For example, a virtual devices which are created by SOCAT, returns the
EINVAL error when the ioctl does query of line states.

Change-Id: Iece3b773fdc8fe4b97951ccf7cff9d2670f24694
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>

src/serialport/qserialport_unix.cpp

@@ -928,6 +928,26 @@ QSerialPort::SerialPortError QSerialPortPrivate::decodeSystemError() const
     case ENXIO:
         error = QSerialPort::ResourceError;
         break;
+#endif
+#ifdef EINVAL
+    case EINVAL:
+        error = QSerialPort::UnsupportedOperationError;
+        break;
+#endif
+#ifdef ENOIOCTLCMD
+    case ENOIOCTLCMD:
+        error = QSerialPort::UnsupportedOperationError;
+        break;
+#endif
+#ifdef ENOTTY
+    case ENOTTY:
+        error = QSerialPort::ResourceError;
+        break;
+#endif
+#ifdef EPERM
+    case EPERM:
+        error = QSerialPort::PermissionError;
+        break;
 #endif
     default:
         error = QSerialPort::UnknownError;