[build] Remove unused import

Change-Id: I22e5fe372057106c56dfbdc111aedbb82f9bd595
diff --git a/BUILD.gn b/BUILD.gn
index 3e20e7b..4641602 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -2,8 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//build/config/arm.gni")
-
 # If fixed point implementation shall be used (otherwise float).
 use_opus_fixed_point = current_cpu == "arm64"