Add constexpr to registries

Because these structures are known at compile time, they can be
constexpr with no ill effect.

Tested:  Code compiles, clang-tidy checks pass no functional change.

Signed-off-by: Ed Tanous <ed.tanous@intel.com>
Signed-off-by: James Feist <james.feist@linux.intel.com>
Change-Id: Id78e3638b3dddd740f1a22e22d17fb0d6f8437d3
diff --git a/redfish-core/include/registries/base_message_registry.hpp b/redfish-core/include/registries/base_message_registry.hpp
index 1c429c5..f9009f1 100644
--- a/redfish-core/include/registries/base_message_registry.hpp
+++ b/redfish-core/include/registries/base_message_registry.hpp
@@ -33,7 +33,7 @@
     "1.4.0",
     "DMTF",
 };
-const std::array<MessageEntry, 58> registry = {
+constexpr std::array<MessageEntry, 58> registry = {
     MessageEntry{
         "AccessDenied",
         {
diff --git a/redfish-core/include/registries/openbmc_message_registry.hpp b/redfish-core/include/registries/openbmc_message_registry.hpp
index c460987..fc96952 100644
--- a/redfish-core/include/registries/openbmc_message_registry.hpp
+++ b/redfish-core/include/registries/openbmc_message_registry.hpp
@@ -29,7 +29,7 @@
     "0.1.0",
     "OpenBMC",
 };
-const std::array<MessageEntry, 134> registry = {
+constexpr std::array<MessageEntry, 134> registry = {
     MessageEntry{
         "ADDDCCorrectable",
         {