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/file.hpp b/file.hpp
index d762012..1c9c887 100644
--- a/file.hpp
+++ b/file.hpp
@@ -1,7 +1,7 @@
 #pragma once
 
 #include <unistd.h>
-namespace witherspoon
+namespace phosphor
 {
 namespace power
 {
@@ -68,4 +68,4 @@
 
 } // namespace util
 } // namespace power
-} // namespace witherspoon
+} // namespace phosphor