Revert "org-compat.el: Require 'org-agenda in a timely fashion"

This reverts commit 2f30ecffdfbd30075add115beac953098fd4160f.

lisp/org-compat.el

@@ -1048,9 +1048,7 @@ key."
 		   #'org-agenda-diary-entry)))
 
 (eval-after-load "calendar"
-  '(progn
-     (require 'org-agenda)
-     (add-hook 'calendar-mode-hook #'org--setup-calendar-bindings)))
+  '(add-hook 'calendar-mode-hook #'org--setup-calendar-bindings))
 
 ;;;; Saveplace