V4L/DVB (4387): Add Kconfig infrastructure for dvb_attach

Allow it to be en/disabled
Disable it in < 2.6.17 due to symbol_xxx() bug

Signed-off-by: Andrew de Quincey <adq_dvb@lidskialf.net>
Acked-by: Michael Krufky <mkrufky@linuxtv.org>
Acked-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/dvb/frontends/isl6421.h b/drivers/media/dvb/frontends/isl6421.h
index b5deacf..1916e3e 100644
--- a/drivers/media/dvb/frontends/isl6421.h
+++ b/drivers/media/dvb/frontends/isl6421.h
@@ -39,8 +39,17 @@
 #define ISL6421_ISEL1	0x20
 #define ISL6421_DCL	0x40
 
+#if defined(CONFIG_DVB_ISL6421) || defined(CONFIG_DVB_ISL6421_MODULE)
 /* override_set and override_clear control which system register bits (above) to always set & clear */
 extern struct dvb_frontend *isl6421_attach(struct dvb_frontend *fe, struct i2c_adapter *i2c, u8 i2c_addr,
 			  u8 override_set, u8 override_clear);
+#else
+static inline struct dvb_frontend *isl6421_attach(struct dvb_frontend *fe, struct i2c_adapter *i2c, u8 i2c_addr,
+						  u8 override_set, u8 override_clear)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __FUNCTION__);
+	return NULL;
+}
+#endif // CONFIG_DVB_ISL6421
 
 #endif