QNX: Fixed build of QPA plugin

Added private core and gui includes to project file. Those were
implicitly included in the past, but removed with commit 289302e6

.
Removed redundant module, as well.

Change-Id: I878d9acabc5497702dc282e25d6fdd9016ae2ad6
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>

src/plugins/platforms/qnx/qnx.pro

 TARGET = qqnx
 
-QT += platformsupport platformsupport-private
+QT += platformsupport-private core-private gui-private
 
 # Uncomment this to build with support for IMF once it becomes available in the BBNDK
 #CONFIG += qqnx_imf