adb: fix clang-format for access modifier dedent.

It was previously -1 (the default from Google style, since it uses 2
space indentation), instead of -2.

Change-Id: I1865505ce17a2cc13b85de58bda55c3b1dfcf08c
diff --git a/.clang-format b/.clang-format
index 6737535..fc4eb1b 100644
--- a/.clang-format
+++ b/.clang-format
@@ -2,6 +2,7 @@
 AllowShortBlocksOnASingleLine: false
 AllowShortFunctionsOnASingleLine: false
 
+AccessModifierOffset: -2
 ColumnLimit: 100
 CommentPragmas: NOLINT:.*
 DerivePointerAlignment: false