iio: st-sensors: add configuration for WhoAmI address

This patch permits to configure the WhoAmI register address
because some device could have not a standard address for
this register.

Signed-off-by: Giuseppe Barba <giuseppe.barba@st.com>
Reviewed-by: Denis Ciocca <denis.ciocca@st.com>
Acked-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
6 files changed