iio: magnetometer: hmc5843: Remove duplicate 'the'

Fix an obvious typing error, found by spellcheck(1).

Signed-off-by: Jiang Jian <jiangjian@cdjrlc.com>
Link: https://lore.kernel.org/r/20220622035925.5008-1-jiangjian@cdjrlc.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>