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