meta-digi-dey: fix wifi-related functionality overrides for ccimx91

Some wifi-related functionality was enabled on ccimx93 overrides. The
ccimx91 also needs this functionality but it was not being applied as
the overrides were only for ccimx93.

Generalize the overrides for ccimx9.

https://onedigi.atlassian.net/browse/DEL-9214

Signed-off-by: Javier Viguera <javier.viguera@digi.com>

meta-digi-dey/recipes-core/busybox/busybox/ccimx9/standby-actions

@@ -67,7 +67,7 @@ if [ "${1}" = "pre" ]; then
 		RESUME_ACTIONS="${RESUME_ACTIONS_BT}"
 	fi
 	if [ -n "${RESUME_ACTIONS_WIFI}" ]; then
-		if [ ! -n "${RESUME_ACTIONS_BT}" ]; then
+		if [ -z "${RESUME_ACTIONS_BT}" ]; then
 			RESUME_ACTIONS="sleep 0.5;"
 		fi
 		RESUME_ACTIONS="${RESUME_ACTIONS}${RESUME_ACTIONS_WIFI}"