Remove the useless define

The less we have define for pm blocks the easier is to add more pm blocks.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/display.h b/display.h
index ebd501a..f354195 100644
--- a/display.h
+++ b/display.h
@@ -13,6 +13,8 @@
  *       - initial API and implementation
  *******************************************************************************/
 
+enum { CLOCK, REGULATOR, SENSOR };
+
 struct display_ops {
 	int (*display)(void);
 	int (*select)(void);