catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ia8f2ae95679f98f2fc3f32239bbf3b3578c35888
diff --git a/extensions/phal/phal_error.cpp b/extensions/phal/phal_error.cpp
index d769d11..b6dc1d7 100644
--- a/extensions/phal/phal_error.cpp
+++ b/extensions/phal/phal_error.cpp
@@ -492,7 +492,7 @@
         openpower::pel::createBootErrorPEL(pelAdditionalData,
                                            jsonCalloutDataList);
     }
-    catch (std::exception& ex)
+    catch (const std::exception& ex)
     {
         reset();
         throw ex;
@@ -595,7 +595,7 @@
             logLevel = std::stoi(env_p);
         }
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         log<level::ERR>(("Conversion Failure"), entry("ENVIRONMENT=%s", env),
                         entry("EXCEPTION=%s", e.what()));