kernel.bbclass only install image in do_deploy if not installing from packaged staging

kernel.bbclass only install image in do_deploy if not installing from packaged staging

kernel.bbclass do_deploy has:
install -m 0644 ${KERNEL_OUTPUT} ${DEPLOY_DIR_IMAGE}/${KERNEL_IMAGE_BASE_NAME}.bin
which expands to
install -m 0644 arch/arm/boot/uImage .../deploy/glibc/images/beagleboard/uImage-2.6.29-r51-beagleboard.bin
but in packaged staging  arch/arm/boot/uImage does not exist so we get the error:
install: cannot stat `arch/arm/boot/uImage': No such file or directory
This patch only installs uImage if not using packaged staging

Signed-off-by: Frans Meulenbroeks <fransmeulenbroeks@gmail.com>