qemu: Add qemu-common package

qemu: Add qemu-common package

We split the qemu package [1] to add support to make user can install
one qemu arch emulation rpm to ease the concerns who care much about
the rpm size in embedded device.

But for the user who only install the qemu-*.rpm can't do anything
except they install the qemu emulation rpm like qemu-system-x86-64-*.rpm
explicitly.

So add qemu-common package to package all thing into qemu-common when
not split the package, and package only the basic into qemu-common and
other arch related to each qemu arch emulation rpm when split the package
to fix the backward compatibility.

qenu-*.rpm which is meta package rdepends on qemu-common and the available
qemu arch emulation rpm like qemu-system-x86-64-*.rpm and etc.

[1] https://git.openembedded.org/openembedded-core/commit/?id=893846ead7ee54d53e9076150cd655e0c8bca5db

Signed-off-by: Mingli Yu <mingli.yu@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>