kselftest: dt: Ignore nodes that have ancestors disabled

kselftest: dt: Ignore nodes that have ancestors disabled

Filter out nodes that have one of its ancestors disabled as they aren't
expected to probe.

This removes the following false-positive failures on the
sc7180-trogdor-lazor-limozeen-nots-r5 platform:

/soc@0/geniqup@8c0000/i2c@894000/proximity@28
/soc@0/geniqup@ac0000/spi@a90000/ec@0
/soc@0/remoteproc@62400000/glink-edge/apr
/soc@0/remoteproc@62400000/glink-edge/apr/service@3
/soc@0/remoteproc@62400000/glink-edge/apr/service@4
/soc@0/remoteproc@62400000/glink-edge/apr/service@4/clock-controller
/soc@0/remoteproc@62400000/glink-edge/apr/service@4/dais
/soc@0/remoteproc@62400000/glink-edge/apr/service@7
/soc@0/remoteproc@62400000/glink-edge/apr/service@7/dais
/soc@0/remoteproc@62400000/glink-edge/apr/service@8
/soc@0/remoteproc@62400000/glink-edge/apr/service@8/routing
/soc@0/remoteproc@62400000/glink-edge/fastrpc
/soc@0/remoteproc@62400000/glink-edge/fastrpc/compute-cb@3
/soc@0/remoteproc@62400000/glink-edge/fastrpc/compute-cb@4
/soc@0/remoteproc@62400000/glink-edge/fastrpc/compute-cb@5
/soc@0/spmi@c440000/pmic@0/pon@800/pwrkey

Fixes: 14571ab1ad21 ("kselftest: Add new test for detecting unprobed Devicetree devices")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20240729-dt-kselftest-parent-disabled-v2-1-d7a001c4930d@collabora.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>