Eliminate compiler/lint warning introduced by futures hack.

Change-Id: I280fdd97bf9f46c880cd34eb2e88a8abac96c489
diff --git a/core/src/entry_point/start_item_riscv32.rs b/core/src/entry_point/start_item_riscv32.rs
index 3538530..6c3f917 100644
--- a/core/src/entry_point/start_item_riscv32.rs
+++ b/core/src/entry_point/start_item_riscv32.rs
@@ -3,7 +3,6 @@
 #[doc(hidden)]
 #[naked]
 #[no_mangle]
-#[allow(named_asm_labels)]
 #[link_section = ".start"]
 // The args for this function are:
 //    app_start: usize,