iio: light: vcnl4000: Set ps high definition for 4040/4200

iio: light: vcnl4000: Set ps high definition for 4040/4200

The vcnl4040/vcnl4200 proximity sensor defaults to 12 bit data
resolution, but the chip also supports 16 bit data resolution, which is
called proximity high definition (PS_HD).

Make the vcnl4040/vcnl4200 proximity sensor use the high definition for
all data readings. Please note that in order to preserve the 12 bit
integer part of the in_proximity_raw output, the format is changed from
integer to fixed point.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
Link: https://lore.kernel.org/r/20231221-vcnl4000-ps-hd-v3-1-6dcc889372be@axis.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>