iio: hid-sensors: lighten exported symbols by moving to IIO_HID namespace

iio: hid-sensors: lighten exported symbols by moving to IIO_HID namespace

A namespace for exported symbols makes clear who is a provider
and who is a consumer of the certain resources. Besides that,
it doesn't pollute the common namespace.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://lore.kernel.org/r/20210614162447.5392-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>