Add the spot for spot metering mode.

Not yet fully documented in QML - needs a bit of an overhaul first.

Change-Id: Ic11684858fb872d0b4dcedf60b390571371db252
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>

src/multimedia/controls/qcameraexposurecontrol.h

@@ -72,6 +72,7 @@ public:
         ExposureCompensation = 4,
         FlashPower = 5,
         FlashCompensation = 6,
+        SpotMeteringPoint = 7,
         ExtendedExposureParameter = 1000
     };