media: dvb_frontend: ensure that inital front end status initialized

The fe_status variable s is not initialized meaning it can have any
random garbage status.  This could be problematic if fe->ops.tune is
false as s is not updated by the call to fe->ops.tune() and a
subsequent check on the change status will using a garbage value.
Fix this by adding FE_NONE to the enum fe_status and initializing
s to this.

Detected by CoverityScan, CID#112887 ("Uninitialized scalar variable")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NShuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-core/dvb_frontend.c

@@ -631,7 +631,7 @@ static int dvb_frontend_thread(void *data)
 	struct dvb_frontend *fe = data;
 	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 	struct dvb_frontend_private *fepriv = fe->frontend_priv;
-	enum fe_status s;
+	enum fe_status s = FE_NONE;
 	enum dvbfe_algo algo;
 	bool re_tune = false;
 	bool semheld = false;

include/uapi/linux/dvb/frontend.h

@@ -127,6 +127,7 @@ enum fe_sec_mini_cmd {
  *			to reset DiSEqC, tone and parameters
  */
 enum fe_status {
+	FE_NONE			= 0x00,
 	FE_HAS_SIGNAL		= 0x01,
 	FE_HAS_CARRIER		= 0x02,
 	FE_HAS_VITERBI		= 0x04,