common: code re-org

Move common files under a common/ directory.

Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
Change-Id: I0eaf91d4ee94c1e78228da0c50892f82e91912fa
diff --git a/libpldmresponder/bios_attribute.cpp b/libpldmresponder/bios_attribute.cpp
index f6b3912..b0b834e 100644
--- a/libpldmresponder/bios_attribute.cpp
+++ b/libpldmresponder/bios_attribute.cpp
@@ -3,7 +3,7 @@
 #include "bios_attribute.hpp"
 
 #include "bios_config.hpp"
-#include "utils.hpp"
+#include "common/utils.hpp"
 
 #include <iostream>
 #include <variant>