main/wcnss-wlan: add openrc subpkg (MR 5500)

This means the main package is now empty, but this is fine. In the
future we'll need to add a -systemd subpackage that installs the unit
file + install scripts for implementing what this thing does on systemd.

main/wcnss-wlan/APKBUILD

 # Maintainer Attila Szollosi <ata2001@airmail.cc>
 pkgname=wcnss-wlan
 pkgver=2
-pkgrel=0
+pkgrel=1
 pkgdesc="Init script for enabling wcnss wlan driver (downstream Android kernels)"
 url="https://gitlab.com/postmarketOS/pmaports"
 arch="noarch"
 license="GPL-3.0-or-later"
-install="$pkgname.post-install"
 source="$pkgname.initd"
+subpackages="$pkgname-openrc"
 options="!check" # No tests
 
 package() {
 	install -Dm755 "$srcdir"/$pkgname.initd "$pkgdir"/etc/init.d/wcnss-wlan
 }
+
+openrc() {
+	install="$subpkgname.post-install"
+	default_openrc
+}
+
 sha512sums="
 8bf30e5cdf71dc3e2f4ec5b426abd87036dd8748207ec133c3898c966fa33770f18f852f64a9011f20780c411364fd573a1fa7adba8f4491326026f8d85dd018  wcnss-wlan.initd
 "