Support 0xFF fru_type values

The OCC may put a value of 0xFF as the FRU type for some temperature
sensors to indicate they aren't available on the platform.  In this
case, the OCC device driver won't even make a tempX_input file for them.

Check for this case and just continue on.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I27dbc63270bfc60eed9d93eeb844625572839e38
diff --git a/occ_manager.cpp b/occ_manager.cpp
index 4c979df..ea66cd4 100644
--- a/occ_manager.cpp
+++ b/occ_manager.cpp
@@ -18,6 +18,8 @@
 namespace occ
 {
 
+constexpr uint32_t fruTypeNotAvailable = 0xFF;
+
 using namespace phosphor::logging;
 
 void Manager::findAndCreateObjects()
@@ -258,6 +260,12 @@
 
             if (type == OCC_DIMM_TEMP_SENSOR_TYPE)
             {
+                if (fruTypeValue == fruTypeNotAvailable)
+                {
+                    // Not all DIMM related temps are available to read
+                    // (no _input file in this case)
+                    continue;
+                }
                 auto iter = dimmTempSensorName.find(fruTypeValue);
                 if (iter == dimmTempSensorName.end())
                 {