[media] cec: Add cec_get_drvdata()

Add a helper function to get driver private data from CEC
adapter. This helps the readability a little bit and allows
to change the 'priv' field name to something else without
needing to touch all drivers.
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

include/media/cec.h

@@ -184,6 +184,11 @@ struct cec_adapter {
 	char input_drv[32];
 };
 
+static inline void *cec_get_drvdata(const struct cec_adapter *adap)
+{
+	return adap->priv;
+}
+
 static inline bool cec_has_log_addr(const struct cec_adapter *adap, u8 log_addr)
 {
 	return adap->log_addrs.log_addr_mask & (1 << log_addr);