drm_hwcomposer: Update readability-identifier-naming rules

Sync local rules with github gist [1] revision 7.

[1]: https://gist.github.com/airglow923/1fa3bda42f2b193920d7f46ee8345e04
Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/.clang-tidy b/.clang-tidy
index 221c030..4bd8ff7 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -50,8 +50,10 @@
     value:           '^[A-Z]+(_[A-Z]+)*_$'
   - key:             readability-identifier-naming.MemberCase
     value:           lower_case
-  - key:             readability-identifier-naming.MemberSuffix
+  - key:             readability-identifier-naming.PrivateMemberSuffix
     value:           _
+  - key:             readability-identifier-naming.PublicMemberSuffix
+    value:           ''
   - key:             readability-identifier-naming.NamespaceCase
     value:           lower_case
   - key:             readability-identifier-naming.ParameterCase