qt-mobility: tighten up config generation and use PACKAGECONFIG

qt-mobility: tighten up config generation and use PACKAGECONFIG

* Add DEPENDS on util-linux (for libblkid) and gstreamer (was likely
  always being auto-detected since it is currently an unconditional
  dependency of Qt itself in our Qt recipes)
* Use PACKAGECONFIG to allow individual configuration of pulseaudio and
  bluetooth features rather than additional variables
* Generate a static platform configuration and tell the configure script
  to use that instead of running compile tests during do_configure. This
  should avoid the issue of camerabin sometimes being built and failing
  as seen on the Yocto Project autobuilder.

(From OE-Core rev: 9d64f117cccf69916ce5b08039edcb3a19dc2b58)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>