iio: addac: stx104: Replace bitops.h header inclusion with bits.h

The <linux/bitops.h> header is included in the stx104 driver so that we
can use the BIT() macro. This macro is actually defined in the
<linux/bits.h> header, so replace the <linux/bitops.h> header inclusion
with <linux/bits.h>.

Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/20230318185503.341914-1-william.gray@linaro.org


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>