Merge tag 'drm-misc-fixes-2021-12-16-1' of ssh://git.freedesktop.org/git/drm/drm-misc into drm-fixes

One null pointer dereference fix for ast, a pixel clock unit fix for
simpledrm and a user-space regression revert for fb-helper

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20211216082603.pm6yzlckmxvwnqyv@houat