igvm: fix memory leak on failed memory region init
When memory_region_init_* fail, `igvm_pages` is not freed causing a leak.
Free `igvm_pages` in the error path.
Fixes: c1d466d267cf ("backends/igvm: Add IGVM loader and configuration")
Signed-off-by: Luigi Leonardi <leonardi@redhat.com>
Message-ID: <20260330-igvm_fixes-v1-2-03587a5a808b@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>