Refactor: rename namespace witherspoon to phosphor

This repo now becomes phosphor-power, rename namespace witherspoon to
phosphor to make it generic.

Signed-off-by: Lei YU <mine260309@gmail.com>
Change-Id: Icb9f8a7c33065add99f2bf42ed55745a28fa0424
diff --git a/power-sequencer/runtime_monitor.cpp b/power-sequencer/runtime_monitor.cpp
index fa9ecfe..9dd4550 100644
--- a/power-sequencer/runtime_monitor.cpp
+++ b/power-sequencer/runtime_monitor.cpp
@@ -23,7 +23,7 @@
 #include <org/open_power/Witherspoon/Fault/error.hpp>
 #include <phosphor-logging/log.hpp>
 
-namespace witherspoon
+namespace phosphor
 {
 namespace power
 {
@@ -65,4 +65,4 @@
 }
 
 } // namespace power
-} // namespace witherspoon
+} // namespace phosphor