clang-tidy: Enable readability-redundant-access-specifiers check

Finds classes, structs, and unions containing redundant member
(field and method) access specifiers.

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I6ce8c84fbab98de5efd6a11804f9dc58afae5027
diff --git a/.clang-tidy b/.clang-tidy
index c3291cd..c10e753 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -264,6 +264,7 @@
 readability-misplaced-array-index,
 readability-named-parameter,
 readability-non-const-parameter,
+readability-redundant-access-specifiers,
 readability-redundant-function-ptr-dereference,
 readability-redundant-preprocessor,
 readability-redundant-smartptr-get,