move getEnv methods into env namespace

Move the getEnv(...) methods into the env namespace,
for consistency.

Change-Id: I4055d9456c17f8b20071cdee1b8e531c10fb0c7e
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/targets.hpp b/targets.hpp
index 3c6dc0d..fe256a3 100644
--- a/targets.hpp
+++ b/targets.hpp
@@ -4,6 +4,7 @@
 #include <phosphor-logging/elog-errors.hpp>
 #include <phosphor-logging/log.hpp>
 #include <xyz/openbmc_project/Sensor/Device/error.hpp>
+#include "env.hpp"
 #include "fan_speed.hpp"
 #include "fan_pwm.hpp"
 
@@ -87,7 +88,7 @@
     {
         targetName = pwm;
         // If PWM_TARGET is set, use the specified pwm id
-        auto id = getEnv("PWM_TARGET", sensor);
+        auto id = env::getEnv("PWM_TARGET", sensor);
         if (!id.empty())
         {
             targetId = id;