Revert "shell: Inhibit idle fade-out behavior"

This reverts commit 9be807c69b1249390bb213e5403b9183738777f4.

(Accidental landing)
diff --git a/libweston/compositor.c b/libweston/compositor.c
index a92e764..f503933 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -3930,10 +3930,7 @@
 				       compositor, NULL);
 }
 
-/** Apply a DPMS mode to the compositor's outputs.
- *
- * Outputs may skip setting the DPMS state if they are being used to
- * display an surface that is requesting idle behaviors be inhibited.
+/** Set a DPMS mode on all of the compositor's outputs
  *
  * \param compositor The compositor instance
  * \param state The DPMS state the outputs will be set to