pid: add missing override specifiers

[pid/controller.hpp:18] -> [pid/pidcontroller.hpp:28]: (style) The
function 'inputProc' overrides a function in a base class but is not
marked with a 'override' specifier.
[pid/controller.hpp:20] -> [pid/pidcontroller.hpp:30]: (style) The
function 'outputProc' overrides a function in a base class but is not
marked with a 'override' specifier.
[pid/controller.hpp:22] -> [pid/pidcontroller.hpp:32]: (style) The
function 'process' overrides a function in a base class but is not
marked with a 'override' specifier.
[pid/controller.hpp:24] -> [pid/pidcontroller.hpp:34]: (style) The
function 'getID' overrides a function in a base class but is not marked
with a 'override' specifier.

Change-Id: I29a6bbe644a5f7aad933eb49e7b6f7fdc6e33f19
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/pid/pidcontroller.hpp b/pid/pidcontroller.hpp
index 9c3ee7f..b7aaba6 100644
--- a/pid/pidcontroller.hpp
+++ b/pid/pidcontroller.hpp
@@ -25,13 +25,13 @@
     {
     }
 
-    virtual float inputProc(void) = 0;
+    virtual float inputProc(void) override = 0;
     virtual float setptProc(void) = 0;
-    virtual void outputProc(float value) = 0;
+    virtual void outputProc(float value) override = 0;
 
-    void process(void);
+    void process(void) override;
 
-    std::string getID(void)
+    std::string getID(void) override
     {
         return _id;
     }