meta-facebook: fix phosphor-state-manager build error

The `systemd_system_unitdir` path changs after enabling 'usrmerge',
replace actual path with `systemd_system_unitdir` to avoid build issues
due to path changes.

Add machine name into FILESEXTRAPATHS to fix files not included issue.

Signed-off-by: Potin Lai <potin.lai@quantatw.com>
Change-Id: I5bb58f48dcf5e689ad44265f0b6add50b7d141bd
diff --git a/meta-facebook/recipes-phosphor/state/phosphor-state-manager_%.bbappend b/meta-facebook/recipes-phosphor/state/phosphor-state-manager_%.bbappend
index b0acf75..ce091f4 100644
--- a/meta-facebook/recipes-phosphor/state/phosphor-state-manager_%.bbappend
+++ b/meta-facebook/recipes-phosphor/state/phosphor-state-manager_%.bbappend
@@ -1,4 +1,4 @@
-FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
+FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}/${MACHINE}:"
 
 HOST_DEFAULT_TARGETS:append = " \
     obmc-host-shutdown@{}.target.wants/host-poweroff@{}.service \
@@ -55,6 +55,6 @@
     install -m 0777 ${WORKDIR}/power-ctrl-init ${D}${libexecdir}/${PN}/
 }
 
-FILES:${PN} += " /lib/systemd/system/*.service"
+FILES:${PN} += " ${systemd_system_unitdir}/*.service"
 
 SYSTEMD_SERVICE:${PN}-bmc:append:greatlakes = "power-ctrl-init.service"