[media] dvb: make DVB frontend *_ops instances "const"

These are immutable.  Making them "const" allows the compiler to move
them to the "rodata" section.

Note that cxd2841er_t_c_ops cannot be made "const", because
cxd2841er_attach() modifies it.  Ouch!

[mchehab@s-opensource.com: fix merge conflicts]
Signed-off-by: Max Kellermann <max.kellermann@gmail.com>

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-frontends/stv090x.c

@@ -4880,7 +4880,7 @@ static int stv090x_set_gpio(struct dvb_frontend *fe, u8 gpio, u8 dir,
 	return stv090x_write_reg(state, STV090x_GPIOxCFG(gpio), reg);
 }
 
-static struct dvb_frontend_ops stv090x_ops = {
+static const struct dvb_frontend_ops stv090x_ops = {
 	.delsys = { SYS_DVBS, SYS_DVBS2, SYS_DSS },
 	.info = {
 		.name			= "STV090x Multistandard",