[media] dvb: don't require a parameter for get_frontend

Just like set_frontend, use the dvb cache properties for get_frontend.
This is more consistent, as both functions are now symetric. Also,
at the places get_frontend is called, it makes sense to update the
cache.

Most of this patch were generated by this small perl script:

	while (<>) { $file .= $_; }
	if ($file =~ m/\.get_frontend\s*=\s*([\d\w_]+)/) {
		my $get = $1;
		$file =~ s/($get)(\s*\([^\,\)]+)\,\s*struct\s+dtv_frontend_properties\s*\*\s*([_\d\w]+)\)\s*\{/\1\2)\n{\n\tstruct dtv_frontend_properties *\3 = &fe->dtv_property_cache;/g;
	}
	print $file;

Of course, the changes at dvb_frontend.[ch] were made by hand,
as well as the changes on a few other places, where get_frontend()
is called internally inside the driver.

On some places, get_frontend() were just a void function. Those
occurrences were removed, as the DVB core handles such cases.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/frontends/dib3000mb.c b/drivers/media/dvb/frontends/dib3000mb.c
index de9ed6c..a1c5bdb 100644
--- a/drivers/media/dvb/frontends/dib3000mb.c
+++ b/drivers/media/dvb/frontends/dib3000mb.c
@@ -112,8 +112,7 @@
 		}
 	};
 
-static int dib3000mb_get_frontend(struct dvb_frontend* fe,
-				  struct dtv_frontend_properties *c);
+static int dib3000mb_get_frontend(struct dvb_frontend* fe);
 
 static int dib3000mb_set_frontend(struct dvb_frontend *fe, int tuner)
 {
@@ -360,7 +359,7 @@
 		deb_setf("search_state after autosearch %d after %d checks\n",search_state,as_count);
 
 		if (search_state == 1) {
-			if (dib3000mb_get_frontend(fe, c) == 0) {
+			if (dib3000mb_get_frontend(fe) == 0) {
 				deb_setf("reading tuning data from frontend succeeded.\n");
 				return dib3000mb_set_frontend(fe, 0);
 			}
@@ -451,9 +450,9 @@
 	return 0;
 }
 
-static int dib3000mb_get_frontend(struct dvb_frontend* fe,
-				  struct dtv_frontend_properties *c)
+static int dib3000mb_get_frontend(struct dvb_frontend* fe)
 {
+	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 	struct dib3000_state* state = fe->demodulator_priv;
 	fe_code_rate_t *cr;
 	u16 tps_val;