CONF: cleanup of sti-96bc2
CONF: cleanup of sti-96bc2

- change tune configuration
- clean image install
- remove PACKAGECONFIG and PREFERRED

Signed-off-by: Christophe Priouzeau <764d1e7ac3bcfb3c2f77ddc550eda7ed9b72ff9f@st.com>

cpriouzeau/meta-st-cannes2,cpriouzeau/meta-st-cannes2