Update git submodules

* Update docs/submodules/doctor from branch 'master'
  - Fraser 6.1.0

    Change-Id: Id26ebd8438f26f60efe3f433e6c46ae76ab95d4a
    Signed-off-by: Tomi Juvonen <tomi.juvonen@nokia.com>

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index aeb2ff1..db301ed 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit aeb2ff16a530c7c7af9a6e2d16ba5421dd074cff
+Subproject commit db301edb5a06109628af0b2e3416751615f11153