psu-ng: Change paths of SN/PN/FN files

The cffps2 power supply device driver started showing these fields under
new names in a different directory.  Eventually, the ones in the
original location will be removed.

Old path: /sys/kernel/debug/pmbux/hwmonX/cffps2
New path: /sys/kernel/debug/pmbux/hwmonX

Old name       New Name
-------------------------
fru            mfr_model
part_number    mfr_revision
header         mfr_location
serial_number  mfr_serial

Tested:
Compared the results of introspecting the PS inventory before and after
the changes as the application puts these 4 fields into the inventory.

Change-Id: I0614396c28c08df22d57f88f8be1920d63a10132
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/phosphor-power-supply/power_supply.hpp b/phosphor-power-supply/power_supply.hpp
index da6adad..c28c11e 100644
--- a/phosphor-power-supply/power_supply.hpp
+++ b/phosphor-power-supply/power_supply.hpp
@@ -21,10 +21,10 @@
 #if IBM_VPD
 // PMBus device driver "file name" to read for CCIN value.
 constexpr auto CCIN = "ccin";
-constexpr auto PART_NUMBER = "part_number";
-constexpr auto FRU_NUMBER = "fru";
-constexpr auto SERIAL_HEADER = "header";
-constexpr auto SERIAL_NUMBER = "serial_number";
+constexpr auto PART_NUMBER = "mfr_revision";
+constexpr auto FRU_NUMBER = "mfr_model";
+constexpr auto SERIAL_HEADER = "mfr_location";
+constexpr auto SERIAL_NUMBER = "mfr_serial";
 constexpr auto FW_VERSION = "fw_version";
 
 // The D-Bus property name to update with the CCIN value.