[media] st-hva: encoding summary at instance release

This patch adds a short summary about the encoding operation at each
instance closing, for debug purpose (through dev_dbg()):
- information about the frame (format, resolution)
- information about the stream (format, profile, level, resolution)
- number of encoded frames
- potential (system, encoding...) errors

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Jean-Christophe Trotin <jean-christophe.trotin@st.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>