repo: Update root .clang-format file

Change-Id: Id47dc032bd82c096263531c8a3ec9237d6ef8d79
diff --git a/.clang-format b/.clang-format
index 548df8d..252859b 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,6 +1,7 @@
 ---
-# We'll use defaults from the LLVM style, but with 4 columns indentation.
+# Use defaults from LLVM style with the following exceptions:
 BasedOnStyle: LLVM
 IndentWidth: 4
+ColumnLimit: 132
 SortIncludes: false
 ...