[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/dib7000p.c b/drivers/media/dvb/frontends/dib7000p.c
index c92c1a0..361bdb1 100644
--- a/drivers/media/dvb/frontends/dib7000p.c
+++ b/drivers/media/dvb/frontends/dib7000p.c
@@ -1384,9 +1384,9 @@
 	return 0;
 }
 
-static int dib7000p_get_frontend(struct dvb_frontend *fe,
-				 struct dtv_frontend_properties *fep)
+static int dib7000p_get_frontend(struct dvb_frontend *fe)
 {
+	struct dtv_frontend_properties *fep = &fe->dtv_property_cache;
 	struct dib7000p_state *state = fe->demodulator_priv;
 	u16 tps = dib7000p_read_word(state, 463);
 
@@ -1482,7 +1482,7 @@
 
 static int dib7000p_set_frontend(struct dvb_frontend *fe)
 {
-	struct dtv_frontend_properties *fep = &fe->dtv_property_cache, tmp;
+	struct dtv_frontend_properties *fep = &fe->dtv_property_cache;
 	struct dib7000p_state *state = fe->demodulator_priv;
 	int time, ret;
 
@@ -1509,7 +1509,6 @@
 		fep->guard_interval == GUARD_INTERVAL_AUTO || fep->modulation == QAM_AUTO || fep->code_rate_HP == FEC_AUTO) {
 		int i = 800, found;
 
-		tmp = *fep;
 		dib7000p_autosearch_start(fe);
 		do {
 			msleep(1);
@@ -1520,7 +1519,7 @@
 		if (found == 0 || found == 1)
 			return 0;
 
-		dib7000p_get_frontend(fe, &tmp);
+		dib7000p_get_frontend(fe);
 	}
 
 	ret = dib7000p_tune(fe);