Minor fixes detected with "scripts/checkpatch.pl --strict"

Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180515203736.9224-1-philippe.cornu@st.com