media: cec: move cec_register_cec_notifier to cec-notifier.h

The cec_register_cec_notifier function was in media/cec.h, but it
has to be in cec-notifier.h.

While we are at it, also document it and add a stub function for when
the notifier is disabled or the CEC core code is unreachable.

Based on an earlier patch from Jose Abreu <Jose.Abreu@synopsys.com>.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

include/media/cec-notifier.h

@@ -86,6 +86,14 @@ void cec_notifier_register(struct cec_notifier *n,
  */
 void cec_notifier_unregister(struct cec_notifier *n);
 
+/**
+ * cec_register_cec_notifier - register the notifier with the cec adapter.
+ * @adap: the CEC adapter
+ * @notifier: the CEC notifier
+ */
+void cec_register_cec_notifier(struct cec_adapter *adap,
+			       struct cec_notifier *notifier);
+
 #else
 static inline struct cec_notifier *cec_notifier_get(struct device *dev)
 {
@@ -116,6 +124,10 @@ static inline void cec_notifier_unregister(struct cec_notifier *n)
 {
 }
 
+static inline void cec_register_cec_notifier(struct cec_adapter *adap,
+					     struct cec_notifier *notifier)
+{
+}
 #endif
 
 #endif

include/media/cec.h

@@ -361,11 +361,6 @@ u16 cec_phys_addr_for_input(u16 phys_addr, u8 input);
  */
 int cec_phys_addr_validate(u16 phys_addr, u16 *parent, u16 *port);
 
-#ifdef CONFIG_CEC_NOTIFIER
-void cec_register_cec_notifier(struct cec_adapter *adap,
-			       struct cec_notifier *notifier);
-#endif
-
 #else
 
 static inline int cec_register_adapter(struct cec_adapter *adap,