qt4-tools-nativesdk: fix compile failure in src/dbus

qt4-tools-nativesdk: fix compile failure in src/dbus

[Qt #17962]   -- http://bugreports.qt.nokia.com/browse/QTBUG-17962
[YOCTO #1168] -- http://bugzilla.pokylinux.org/show_bug.cgi?id=1168

Fix "invalid conversion from 'const void*' to 'void*'" error compiling
src/dbus/qdbusintegrator.cpp. It is assumed that the use of "const" here
is incorrect as no other usage of Q_GLOBAL_STATIC_WITH_ARGS uses const
prefix on the first (TYPE) argument.

Patch was imported from the Qt bug tracker (see above reference); the
patch was rejected but for procedural rather than validity reasons.

Fixes [YOCTO #1168]

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>