Fix double close.

resetTty() already does close the fd.
Fixes coverity CID89074.

Change-Id: I2d5fe9bf40b03ed5c249713c64f1dc2ae58ea84b
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

src/plugins/platforms/linuxfb/qlinuxfbscreen.cpp

@@ -292,10 +292,8 @@ QLinuxFbScreen::~QLinuxFbScreen()
         close(mFbFd);
     }
 
-    if (mTtyFd != -1) {
+    if (mTtyFd != -1)
         resetTty(mTtyFd, mOldTtyMode);
-        close(mTtyFd);
-    }
 
     delete mBlitter;
 }