qt4-native: update configure paths to match target

qt4-native: update configure paths to match target

qmake2 was being built with paths different to the target Qt.

The incorrect paths can be seen by running qmake2 -query:
QT_INSTALL_DOCS:${STAGING_DIR_NATIVE}/usr/doc
  should be /usr/share/doc/qt4
QT_INSTALL_PLUGINS:${STAGING_DIR_NATIVE}/usr/plugins
  should be /usr/lib/qt4/plugins
QT_INSTALL_IMPORTS:${STAGING_DIR_NATIVE}/usr/imports
  should be /usr/lib/qt4/imports
QT_INSTALL_TRANSLATIONS:${STAGING_DIR_NATIVE}/usr/translations
  should be /usr/share/qt4/translations
QT_INSTALL_EXAMPLES:${STAGING_DIR_NATIVE}/usr/examples
  should be /usr/bin/qt4/examples
QT_INSTALL_DEMOS:${STAGING_DIR_NATIVE}/usr/demos
  should be /usr/bin/qt4/demos
QMAKE_MKSPECS:${STAGING_DIR_NATIVE}/usr/mkspecs
  should be /usr/share/qt4/mkspecs

Use the same paths as target Qt for consistency. As the mkspecs are
installed to /usr/share/qt4/mkspecs not /usr/mkspecs, qmake2 was
unable to detect and load the webkit module (it is detected by loading
modules/qt_*.pri inside the mkspecs directory) so webkit was missing
from QT_CONFIG if a qmake project reads the QT_CONFIG variable.

(From OE-Core rev: 37b57b44ff83c718021da4f717fc66a28204c96c)

Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>