mk: print target when reporting build complete
mk: print target when reporting build complete

When a target is finished building, it reports just "Build complete".
When building multiple targets simultaneously, e.g.
	make install T=x86_64-native-linuxapp-*
and one target fails, it's not always obvious which of the builds
failed. To help this, we add the actual target that is completed to the
"Build complete" message.

Signed-off-by: Bruce Richardson <66b9e8e8fbd5e9f41f91b0af050876182ce9d0e4@intel.com>

msune/dpdk,venkynv/dpdk-mirror,venkynv/dpdk-mirror,tsphillips/dpdk-fork,mixja/dpdk,msune/dpdk,tsphillips/dpdk-fork,msune/dpdk,mixja/dpdk,mixja/dpdk,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,msune/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror,tsphillips/dpdk-fork,mixja/dpdk