Typo fix.

Change-Id: Ic97ff70842b751c1f9544ccb54433eed388a6131
diff --git a/build/toolchain/embedded.gni b/build/toolchain/embedded.gni
index d3d9f01..4372904 100644
--- a/build/toolchain/embedded.gni
+++ b/build/toolchain/embedded.gni
@@ -298,7 +298,7 @@
 # Specialize for different architectures.
 
 template("aarch64_common_toolchain") {
-  assert(defined(invoker.cpu), "\"cpu\" must be defiend for ${target_name}.")
+  assert(defined(invoker.cpu), "\"cpu\" must be defined for ${target_name}.")
   assert(defined(invoker.target),
          "\"target\" must be defined for ${target_name}")
   assert(defined(invoker.tool_prefix),