PEL: Filled in PEL value descriptions

Updated getValue to return value description instead of registry name.
Updated unit test to add checking of value description.

Testing: Ran unit test successfully on QEMU and also verified peltool
output

Signed-off-by: Harisuddin Mohamed Isa <harisuddin@gmail.com>
Change-Id: Icf64f51a467c3bd4dd9bbcd78aea3df966b20eb7
diff --git a/test/openpower-pels/pel_values_test.cpp b/test/openpower-pels/pel_values_test.cpp
index 50a672d..843cb07 100644
--- a/test/openpower-pels/pel_values_test.cpp
+++ b/test/openpower-pels/pel_values_test.cpp
@@ -30,6 +30,7 @@
     ASSERT_NE(s, subsystemValues.end());
     ASSERT_EQ(0x58, std::get<fieldValuePos>(*s));
     ASSERT_EQ("cec_clocks", std::get<registryNamePos>(*s));
+    ASSERT_EQ("CEC Hardware: Clock", std::get<descriptionPos>(*s));
 
     s = findByValue(0xFF, subsystemValues);
     ASSERT_EQ(s, subsystemValues.end());