Define enum inside the honeywell,transfer-function property block.

Set the correct irq edge in the example block.
Based on the datasheet, in table 13 on page 11:
"End-of-conversion indicator: This pin is set high when a measurement
and calculation have been completed and the data is ready to be
clocked out"

Add description on End-of-conversion interrupt.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Co-developed-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
Link: https://lore.kernel.org/r/20231229092445.30180-2-petre.rodan@subdimension.roSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>