udev: Allow tpm devices to be used as systemd dependencies

This will allow tpm2-abrmd.service to have "After=dev-tpm0.device",
ensuring that it doesn't start too early (without needing to rely on
systemd-udev-settle, which is unnecessarily broad).

Signed-off-by: Mantas Mikulėnas <grawity@gmail.com>

diff --git a/dist/tpm-udev.rules b/dist/tpm-udev.rules
index 96d2c46..e023629 100644
--- a/dist/tpm-udev.rules
+++ b/dist/tpm-udev.rules

@@ -1,4 +1,4 @@
 # tpm devices can only be accessed by the tss user but the tss
 # group members can access tpmrm devices
-KERNEL=="tpm[0-9]*", MODE="0660", OWNER="tss"
-KERNEL=="tpmrm[0-9]*", MODE="0660", OWNER="tss", GROUP="tss"
+KERNEL=="tpm[0-9]*", TAG+="systemd", MODE="0660", OWNER="tss"
+KERNEL=="tpmrm[0-9]*", TAG+="systemd", MODE="0660", OWNER="tss", GROUP="tss"