We have many files that apparently do not depend on the target CPU
configuration, i.e. which can be put into common-obj-y instead of
obj-y. This way, the code can be shared for example between
qemu-system-arm and qemu-system-aarch64, or the various big and
little endian variants like qemu-system-sh4 and qemu-system-sh4eb,
so that we do not have to compile the code multiple times anymore.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200130133841.10779-1-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>