V4L/DVB (6878): tuner: remove extraneous variable declaration

tuner_count is already declared as "extern unsigned const int"
in <media/tuner-types.h>  -- Remove it from tuner-driver.h
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/tuner-driver.h

@@ -24,8 +24,6 @@
 
 #include "dvb_frontend.h"
 
-extern unsigned const int tuner_count;
-
 struct analog_demod_info {
 	char *name;
 };