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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring (Arm) <[e-mail]>

tools/testing/selftests/dt/test_unprobed_devices.sh

···
 		# Check if node is available
 		if [[ -e "${node}"/status ]]; then
 			status=$(tr -d '\000' < "${node}"/status)
-			[[ "${status}" != "okay" && "${status}" != "ok" ]] && continue
+			if [[ "${status}" != "okay" && "${status}" != "ok" ]]; then
+				if [ -n "${disabled_nodes_regex}" ]; then
+					disabled_nodes_regex="${disabled_nodes_regex}|${node}"
+				else
+					disabled_nodes_regex="${node}"
+				fi
+				continue
+			fi
 		fi
+
+		# Ignore this node if one of its ancestors was disabled
+		if [ -n "${disabled_nodes_regex}" ]; then
+			echo "${node}" | grep -q -E "${disabled_nodes_regex}" && continue
+		fi
+
 		echo "${node}" | sed -e 's|\/proc\/device-tree||'
 	done | sort
 	)