packaging: qemu-snp-experimental: support host kernel with gmem

This is required to allow creation of SNP coco on host kernel
(e.g. https://github.com/AMDESE/linux ,branch:snp-host-latest)
supporting guest private memory for SNP using gmem.

Note: This qemu does not work if the host kernel does not support
gmem/UPM.

Fixes: #9092

Signed-off-by: Niteesh Dubey <niteesh@us.ibm.com>

tools/packaging/static-build/qemu/Dockerfile

@@ -60,6 +60,7 @@ RUN apt-get update && apt-get upgrade -y && \
 	    patch \
 	    python \
 	    python-dev \
+	    python3-venv \
 	    rsync \
 	    zlib1g-dev${DPKG_ARCH} && \
     if [ "${ARCH}" != s390x ]; then apt-get install -y --no-install-recommends libpmem-dev${DPKG_ARCH}; fi && \