systemd: avoid failing if no udev rules provided

In the case when no udev rules are provided by the recipe the do_install
step of systemd is failing with:

    install: cannot stat '<WORKDIR>/*.rules': No such file or directory

By default the systemd recipe provides touchscreen.rules but in the
case this is unwanted on target the install step fails. This solution
is dynamic and search for *.rules files in $WORKDIR. If found they are
installed.

(From OE-Core rev: c65eb4c38b61509ad38da19b986e0f06923f0cea)

Signed-off-by: Peter Bergin <peter@berginkonsult.se>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/systemd/systemd_246.2.bb

@@ -232,7 +232,9 @@ do_install() {
 
 	install -d ${D}${sysconfdir}/udev/rules.d/
 	install -d ${D}${sysconfdir}/tmpfiles.d
-	install -m 0644 ${WORKDIR}/*.rules ${D}${sysconfdir}/udev/rules.d/
+	for rule in $(find ${WORKDIR} -maxdepth 1 -type f -name "*.rules"); do
+		install -m 0644 $rule ${D}${sysconfdir}/udev/rules.d/
+	done
 
 	install -m 0644 ${WORKDIR}/00-create-volatile.conf ${D}${sysconfdir}/tmpfiles.d/