All sensors should return a target speed value

All tach sensors associated with a fan should return a target speed
sensor from its getTarget function. In the case where a target speed
sensor does not exist for the tach sensor, it retrieves and returns the
target speed value from the fan where the fan finds the target speed
value from a tach sensor the fan contains that provides it.

Resolves openbmc/openbmc#2784

Change-Id: Iea5561b0aad6942be52af262c7255c60e5e75c7a
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/monitor/tach_sensor.hpp b/monitor/tach_sensor.hpp
index ba3465a..4e57ef5 100644
--- a/monitor/tach_sensor.hpp
+++ b/monitor/tach_sensor.hpp
@@ -63,10 +63,7 @@
         /**
          * @brief Returns the target speed value
          */
-        inline uint64_t getTarget() const
-        {
-            return _tachTarget;
-        }
+        uint64_t getTarget() const;
 
         /**
          * @brief Returns the input speed value