kconfig qconf: fix the type of the desktop widget

QApplication::desktop() returns a pointer to QDesktopWidget, not to
QWidget.

Fixes the following compiler error after a quick conversion with 'qt3to4',
which occured with g++ 3.4.6 and 4.1.2, but not anymore with 4.3.2.

scripts/kconfig/qconf.cc: In constructor 'ConfigMainWindow::ConfigMainWindow()':
scripts/kconfig/qconf.cc:1289: error: cannot convert 'QDesktopWidget*' to 'QWidget*' in initialization
Signed-off-by: Markus Heidelberg <markus.heidelberg@web.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/kconfig/qconf.cc

@@ -5,6 +5,7 @@
 
 #include <qapplication.h>
 #include <qmainwindow.h>
+#include <qdesktopwidget.h>
 #include <qtoolbar.h>
 #include <qlayout.h>
 #include <qvbox.h>
@@ -1275,7 +1276,7 @@ ConfigMainWindow::ConfigMainWindow(void)
 	int x, y, width, height;
 	char title[256];
 
-	QWidget *d = configApp->desktop();
+	QDesktopWidget *d = configApp->desktop();
 	snprintf(title, sizeof(title), _("Linux Kernel v%s Configuration"),
 		getenv("KERNELVERSION"));
 	setCaption(title);