[NO NEW TESTS NEEDED] [FreeBSD] Fix crash when running podman inspect

When preparing container inspection output, ensure we actually have masked paths to work with.
These will only be available on Linux, which is no longer always true as we also support FreeBSD now.

Fixes #21117

Signed-off-by: Ben Cooksley <bcooksley@kde.org>

libpod/container_inspect.go

@@ -315,7 +315,7 @@ func (c *Container) GetSecurityOptions() []string {
 	if apparmor, ok := ctrSpec.Annotations[define.InspectAnnotationApparmor]; ok {
 		SecurityOpt = append(SecurityOpt, fmt.Sprintf("apparmor=%s", apparmor))
 	}
-	if c.config.Spec.Linux.MaskedPaths == nil {
+	if c.config.Spec != nil && c.config.Spec.Linux != nil && c.config.Spec.Linux.MaskedPaths == nil {
 		SecurityOpt = append(SecurityOpt, "unmask=all")
 	}