fixed minor nit as per @terrelln's comments

lib/compress/zstd_compress.c

@@ -265,10 +265,7 @@ static int ZSTD_isUpdateAuthorized(ZSTD_cParameter param)
     case ZSTD_p_ldmMinMatch:
     case ZSTD_p_ldmBucketSizeLog:
     case ZSTD_p_ldmHashEveryLog:
-        return 0;
-
     default:
-        assert(0);
         return 0;
     }
 }

lib/compress/zstdmt_compress.c

@@ -677,7 +677,7 @@ void ZSTDMT_updateCParams_whileCompressing(ZSTDMT_CCtx* mtctx, int compressionLe
                 compressionLevel);
     mtctx->params.compressionLevel = compressionLevel;
     if (compressionLevel != ZSTD_CLEVEL_CUSTOM)
-        cParams = ZSTD_getCParams(compressionLevel, mtctx->frameContentSize, 0 /* should be dictSize */ );
+        cParams = ZSTD_getCParams(compressionLevel, mtctx->frameContentSize, 0 /* dictSize */ );
     cParams.windowLog = saved_wlog;
     mtctx->params.cParams = cParams;
 }