Fix deviceTypeModifier in FRU locator record not set issue

phosphor-host-ipmid[1] assigns `resp.body.deviceTypeModifier = 0x00`
(IPMI FRU Inventory type), but the fb-ipmi-oem code omitted that
assignment and left `resp.body.deviceTypeModifier` in an
indeterminate state. As a result, `ipmitool fru` cannot
determine the device type and reports "Unsupported device"[2].

Fix: explicitly set `resp.body.deviceTypeModifier = 0x00` when
creating/filling the FRU Device Locator Record so the FRU is
recognized correctly by `ipmitool fru`.

Ref:
[1] https://github.com/openbmc/phosphor-host-ipmid/blob/master/dbus-sdr/storagecommands.cpp#L722
[2] https://github.com/openbmc/ipmitool/blob/master/lib/ipmi_fru.c#L3041

Change-Id: Id1e26f36a7249807258f2c10eaa01139ed571fab
Signed-off-by: Alex Wang <alex.ts.wang@fii-foxconn.com>
diff --git a/src/storagecommands.cpp b/src/storagecommands.cpp
index 33c38b2..0a725bc 100644
--- a/src/storagecommands.cpp
+++ b/src/storagecommands.cpp
@@ -542,6 +542,7 @@
     resp.key.channelNumber = 0x0;
     resp.body.reserved = 0x0;
     resp.body.deviceType = 0x10;
+    resp.body.deviceTypeModifier = 0x00;
     resp.body.entityID = 0x0;
     resp.body.entityInstance = 0x1;
     resp.body.oem = 0x0;