deps: Greate deps folder in top-level directory and move cpu_flags in

Greate deps folder in top-level directory in case some dpes used by
more than one folder. e.g both qemu and generic.

Also move qemu/deps/cpu_flags to deps/cpu_flags, as it is  used by both
qemu and provider.

Signed-off-by: Feng Yang <fyang@redhat.com>
provider.cpuflags: Correct command used to compile cpuflags-test

Signed-off-by: Feng Yang <fyang@redhat.com>
Merge pull request #28 from FengYang/deps

Greate deps folder in top-level directory and move cpu_flags in