Fix windows LLVM package name.

Change-Id: Id418705285f11e1625e0023018e60e704bcd0edb
diff --git a/build/tools/build-llvm.py b/build/tools/build-llvm.py
index ecf934c..9b31112 100755
--- a/build/tools/build-llvm.py
+++ b/build/tools/build-llvm.py
@@ -76,7 +76,7 @@
     elif host == 'linux':
         host = 'linux-x86_64'
     elif host == 'windows':
-        host = 'windows-x86'
+        host = 'windows'
 
     package_name = 'llvm-{}-{}.tar.bz2'.format(LLVM_VERSION, host)
     package_path = os.path.join(package_dir, package_name)