hwmonio: split IoAccess object out

Split out the hwmon io access object from the sysfs namespace
into its own.

Change-Id: I8d1a45630117d1d503d0d5fa6061163911b695e8
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/fan_pwm.cpp b/fan_pwm.cpp
index 04cb1b5..cf89552 100644
--- a/fan_pwm.cpp
+++ b/fan_pwm.cpp
@@ -1,6 +1,7 @@
 #include "env.hpp"
 #include "fan_pwm.hpp"
 #include "hwmon.hpp"
+#include "hwmonio.hpp"
 #include "sensorset.hpp"
 #include "sysfs.hpp"
 
@@ -30,8 +31,8 @@
                 type,
                 id,
                 empty,
-                sysfs::hwmonio::retries,
-                sysfs::hwmonio::delay);
+                hwmonio::retries,
+                hwmonio::delay);
         }
         catch (const std::system_error& e)
         {