hw/ppc: spapr: Use qemu_vfree() to free spapr->htab

hw/ppc: spapr: Use qemu_vfree() to free spapr->htab

spapr->htab is allocated by qemu_memalign(), hence we should use
qemu_vfree() to free it.

Fixes: c5f54f3e31bf ("pseries: Move hash page table allocation to reset time")
Fixes: b4db54132ffe ("target/ppc: Implement H_REGISTER_PROCESS_TABLE H_CALL"")
Signed-off-by: Xuzhou Cheng <xuzhou.cheng@windriver.com>
Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220920103159.1865256-28-bmeng.cn@gmail.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>