PHAL: add devtree data export service

Service to export r/w devtree attribute data and
save to a known location.

This service will start after Chassis power is on

Tested: Verified service starts on every boot after
        chassis powered-on.

Signed-off-by: Jayanth Othayoth <ojayanth@in.ibm.com>
Change-Id: I933c3a11fe1532b48a37d7012476b7d574338839
diff --git a/meson.build b/meson.build
index 389c8c2..446912d 100644
--- a/meson.build
+++ b/meson.build
@@ -99,6 +99,7 @@
         'service_files/op-reset-host-check@.service',
         'service_files/op-reset-host-clear.service',
         'service_files/phal-import-devtree@.service',
+        'service_files/phal-export-devtree@.service',
     ]
     unit_subs.set('ENABLE_PHAL_TRUE', '')
 endif
diff --git a/service_files/phal-export-devtree@.service.in b/service_files/phal-export-devtree@.service.in
new file mode 100644
index 0000000..138c210
--- /dev/null
+++ b/service_files/phal-export-devtree@.service.in
@@ -0,0 +1,13 @@
+[Unit]
+Description=Export Host%i PHAL devtree attributes
+Wants=obmc-host-started@%i.target
+After=obmc-host-started@%i.target
+Conflicts=obmc-host-stop@%i.target
+
+[Service]
+RemainAfterExit=yes
+Type=simple
+ExecStart=/usr/bin/phal-export-devtree
+
+[Install]
+WantedBy=obmc-host-startmin@0.target