refactor(st-drivers): improve BSEC driver

Rename driver file to BSEC2.
Split header file in IP and feature parts.
Add functions to access BSEC scratch register.
Several corrections and improvements.
Probe the driver earlier, especially to check debug features.

Change-Id: I1981536398d598d67a19d2d7766dacc18de72ec1
Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Signed-off-by: Yann Gautier <yann.gautier@st.com>
8 files changed