drivers/sensor/lsm6dsl: Fix read/write bus API in shub code

The ce0cc3a7 commit (lsm6dsl: make the driver multi-instance) changes
all bus API signature, which now requires a "const struct device *dev"
and not a "struct lsm6dsl_data *data". By mistake the shub part was
left unchanged. Fix: #28565

Signed-off-by: Armando Visconti <armando.visconti@st.com>