QLocationPermission: make enums have explicit underlying type

They can be smaller than an int, so use quint8. In a world of BC
guarantees, pinning the underlying type of enums is best practice.

Found during API review.

Pick-to: 6.5
Change-Id: I0c31fe4565329982c81173e3a265f73758aad257
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/corelib/kernel/qpermissions.h

@@ -93,13 +93,19 @@ class QLocationPermission
 {
     QT_PERMISSION(QLocationPermission)
 public:
-    enum Accuracy { Approximate, Precise };
+    enum Accuracy : quint8 {
+        Approximate,
+        Precise,
+    };
     Q_ENUM(Accuracy)
 
     Q_CORE_EXPORT void setAccuracy(Accuracy accuracy);
     Q_CORE_EXPORT Accuracy accuracy() const;
 
-    enum Availability { WhenInUse, Always };
+    enum Availability : quint8 {
+        WhenInUse,
+        Always,
+    };
     Q_ENUM(Availability)
 
     Q_CORE_EXPORT void setAvailability(Availability availability);