kconfig qconf: fix namespace for Horizontal and Vertical enum values

They were used as QSplitter::Horizontal resp. QSplitter::Vertical, but
are defined in the 'Qt' namespace.

Fixes the following compiler errors 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 'ConfigSearchWindow::ConfigSearchWindow(ConfigMainWindow*, const char*)':
scripts/kconfig/qconf.cc:1213: error: 'Vertical' is not a member of 'QSplitter'

scripts/kconfig/qconf.cc: In constructor 'ConfigMainWindow::ConfigMainWindow()':
scripts/kconfig/qconf.cc:1304: error: 'Horizontal' is not a member of 'QSplitter'
scripts/kconfig/qconf.cc:1311: error: 'Vertical' is not a member of 'QSplitter'

Signed-off-by: Markus Heidelberg <markus.heidelberg@web.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>