mboxd: Also depend on /dev/aspeed-lpc-ctrl

mboxd opens both /dev/aspeed-mbox and /dev/aspeed-lpc-ctrl devices, so
make sure we depend on both being available prior to service launch.

Change-Id: I388a41b6209b9156e7d7780565d1ed6af483b0a7
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/meta-phosphor/common/recipes-phosphor/mboxd/files/99-aspeed-lpc-ctrl.rules b/meta-phosphor/common/recipes-phosphor/mboxd/files/99-aspeed-lpc-ctrl.rules
new file mode 100644
index 0000000..9cf2fba
--- /dev/null
+++ b/meta-phosphor/common/recipes-phosphor/mboxd/files/99-aspeed-lpc-ctrl.rules
@@ -0,0 +1 @@
+SUBSYSTEM=="misc", KERNEL=="aspeed-lpc-ctrl", TAG+="systemd"