iio: st-sensors: Remove some unused includes and add some that should be there

iio: st-sensors: Remove some unused includes and add some that should be there

The st-sensors drivers have changed in structure over time, and includes
have not always kept up with this.  Let's bring them back to nearer
the ideal.

Identified with the  include-what-you-use tool and careful checking of
its suggestions.

Note I haven't been particularly aggressive here, so this is just the
cases where the include obviously isn't needed rather than the more
subtle corners.

Note I took the opportunity to add mod_devicetable.h as I generally
prefer to see that when acpi or of match tables are present.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Denis Ciocca <denis.ciocca@st.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210608175149.4019289-1-jic23@kernel.org