doc: fix comment mix up in gpiod.h
doc: fix comment mix up in gpiod.h

A couple of the doc comments for GPIOD_LINE_REQUEST_XX values document
the wrong value. Switch them so that they document the appropriate value.

Signed-off-by: Kent Gibson <6bfcbbb63210ea7de0af172018fe9973db4249b7@gmail.com>
Signed-off-by: Bartosz Golaszewski <e5d45fddd9040473413b909b802f629a971ad04c@baylibre.com>

brgl/libgpiod,brgl/libgpiod,brgl/libgpiod,brgl/libgpiod