Using two libraries (libqemuutil.a and libqemustub.a) would sometimes
result in circular dependencies. To avoid these issues let's just
combine both into a single library that functions as both.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Message-Id: <54e6458745493d10901964624479a7d9a872f481.1503077821.git.alistair.francis@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>