[media] drx-j: Fix usage of drxj_close()

This function is currently not used. However, it was meant to
be called at device release. So, add it there.

While here, remove the bad check, as reported by Dan, as
smatch warning:
	drivers/media/dvb-frontends/drx39xyj/drxj.c:20041 drxj_close() warn: variable dereferenced before check 'demod' (see line 20036)
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/dvb-frontends/drx39xyj/drxj.c

@@ -11510,8 +11510,7 @@ static int drxj_close(struct drx_demod_instance *demod)
 	int rc;
 	enum drx_power_mode power_mode = DRX_POWER_UP;
 
-	if ((demod == NULL) ||
-	    (demod->my_common_attr == NULL) ||
+	if ((demod->my_common_attr == NULL) ||
 	    (demod->my_ext_attr == NULL) ||
 	    (demod->my_i2c_dev_addr == NULL) ||
 	    (!demod->my_common_attr->is_opened)) {
@@ -12218,6 +12217,8 @@ static void drx39xxj_release(struct dvb_frontend *fe)
 	struct drx39xxj_state *state = fe->demodulator_priv;
 	struct drx_demod_instance *demod = state->demod;
 
+	drxj_close(demod);
+
 	kfree(demod->my_ext_attr);
 	kfree(demod->my_common_attr);
 	kfree(demod->my_i2c_dev_addr);