device-pine64-pinenote: fix chroot install

`device-pine64-pinenote-systemd.post-install` checks if `tinydm-ebc` was
active via `is-active` systemctl command. This does not work in chroot
environment, and exits with exit code 0, thus acting as if `tinydm-ebc`
is active. Since this check is used for v7-r0 to v8-r0 upgrade, it can
be assumed that if output isn't `active`, then the check should not
pass. This commit reworks this by looking for that output rather than a
zero exit code.

Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/7644>

device/testing/device-pine64-pinenote/APKBUILD

@@ -2,7 +2,7 @@
 pkgname=device-pine64-pinenote
 pkgdesc="Pine64 PineNote"
 pkgver=8
-pkgrel=0
+pkgrel=1
 _commit="28d2c05ab4e80a7972611cd3188f3e8be4197f6a"
 url="https://postmarketos.org"
 license="GPL-3.0-only"

device/testing/device-pine64-pinenote/device-pine64-pinenote-systemd.post-install

@@ -4,7 +4,7 @@
 # allow seamless upgrade 7-r0 to 8-r0, as tinydm-ebc was removed
 # in favor of a systemd override for tinydm
 # TODO: remove in preparation for v26.06
-if systemctl is-active -q tinydm-ebc.service 2>/dev/null; then
+if [ "$(systemctl is-active tinydm-ebc.service 2>/dev/null )" == "active" ]; then
  	systemctl disable tinydm-ebc.service
  	systemctl enable tinydm.service
 fi