V4L/DVB (7943): tuner: add macro, hybrid_tuner_report_instance_count

Create a macro to report the number of instances of the tuner driver
currently in use.  This will allow drivers to perform specific cleanups
before destroying the last instance of a tuner.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/common/tuners/tuner-i2c.h

@@ -170,4 +170,12 @@ __fail:									\
 	__ret;								\
 })
 
+#define hybrid_tuner_report_instance_count(state)			\
+({									\
+	int __ret = 0;							\
+	if (state)							\
+		__ret = state->i2c_props.count;				\
+	__ret;								\
+})
+
 #endif /* __TUNER_I2C_H__ */