many: fix remaining check-pointer-deref issues

The updated parsing_hacks.h file uncovered a bunch of extra
things that the check-pointer-deref coccinelle script flags.

This commit fixes them to make the tree check-pointer-deref clean.

src/nspawn/nspawn-mount.c

@@ -757,12 +757,13 @@ int mount_all(const char *dest,
 }
 
 static int parse_mount_bind_options(const char *options, unsigned long *open_tree_flags, char **mount_opts, RemountIdmapping *idmapping) {
-        unsigned long flags = *open_tree_flags;
+        unsigned long flags = *ASSERT_PTR(open_tree_flags);
         char *opts = NULL;
-        RemountIdmapping new_idmapping = *idmapping;
+        RemountIdmapping new_idmapping = *ASSERT_PTR(idmapping);
         int r;
 
         assert(options);
+        assert(mount_opts);
 
         for (;;) {
                 _cleanup_free_ char *word = NULL;

src/nspawn/nspawn-network.c

@@ -177,6 +177,7 @@ int setup_veth(const char *machine_name,
         assert(machine_name);
         assert(pidref_is_set(pid));
         assert(iface_name);
+        assert(provided_mac);
 
         /* Use two different interface name prefixes depending whether
          * we are in bridge mode or not. */

src/nspawn/nspawn-oci.c

@@ -2082,6 +2082,7 @@ int oci_load(FILE *f, const char *bundle, Settings **ret) {
         int r;
 
         assert_se(bundle);
+        assert(ret);
 
         path = strjoina(bundle, "/config.json");
 

src/nspawn/nspawn.c

@@ -445,6 +445,8 @@ static int parse_capability_spec(const char *spec, uint64_t *ret_mask) {
         uint64_t mask = 0;
         int r;
 
+        assert(ret_mask);
+
         for (;;) {
                 _cleanup_free_ char *t = NULL;