iio: frequency: {admv4420,adrf6780}: format Kconfig entries

Format the entries of these drivers in the Kconfig, where spaces
instead of tabs were used.
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20241007-ad2s1210-select-v2-1-7345d228040f@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>