migration: Properly apply migration compression level parameters

Some glue code was missing, so that using `qmp_migrate_set_parameters`
to set `multifd-zstd-level` or `multifd-zlib-level` did not work. This
commit adds the glue code to fix that.

Signed-off-by: Bryan Zhang <bryan.zhang@bytedance.com>
Link: https://lore.kernel.org/r/20240301035901.4006936-2-bryan.zhang@bytedance.com
Signed-off-by: Peter Xu <peterx@redhat.com>

migration/options.c

@@ -1312,6 +1312,12 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
     if (params->has_multifd_compression) {
         dest->multifd_compression = params->multifd_compression;
     }
+    if (params->has_multifd_zlib_level) {
+        dest->multifd_zlib_level = params->multifd_zlib_level;
+    }
+    if (params->has_multifd_zstd_level) {
+        dest->multifd_zstd_level = params->multifd_zstd_level;
+    }
     if (params->has_xbzrle_cache_size) {
         dest->xbzrle_cache_size = params->xbzrle_cache_size;
     }
@@ -1447,6 +1453,12 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
     if (params->has_multifd_compression) {
         s->parameters.multifd_compression = params->multifd_compression;
     }
+    if (params->has_multifd_zlib_level) {
+        s->parameters.multifd_zlib_level = params->multifd_zlib_level;
+    }
+    if (params->has_multifd_zstd_level) {
+        s->parameters.multifd_zstd_level = params->multifd_zstd_level;
+    }
     if (params->has_xbzrle_cache_size) {
         s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
         xbzrle_cache_resize(params->xbzrle_cache_size, errp);