Fix -[FIRGeoPoint compare:] analysis warning (#3121)

Author: wilhuff

Firestore/Source/API/FIRGeoPoint.mm

@@ -48,15 +48,6 @@ - (instancetype)initWithLatitude:(double)latitude longitude:(double)longitude {
   return self;
 }
 
-- (NSComparisonResult)compare:(FIRGeoPoint *)other {
-  NSComparisonResult result = WrapCompare<double>(self.latitude, other.latitude);
-  if (result != NSOrderedSame) {
-    return result;
-  } else {
-    return WrapCompare<double>(self.longitude, other.longitude);
-  }
-}
-
 #pragma mark - NSObject methods
 
 - (NSString *)description {
@@ -88,6 +79,15 @@ - (id)copyWithZone:(NSZone *_Nullable)zone {
 
 @implementation FIRGeoPoint (Internal)
 
+- (NSComparisonResult)compare:(FIRGeoPoint *)other {
+  NSComparisonResult result = WrapCompare<double>(self.latitude, other.latitude);
+  if (result != NSOrderedSame) {
+    return result;
+  } else {
+    return WrapCompare<double>(self.longitude, other.longitude);
+  }
+}
+
 - (firestore::GeoPoint)toGeoPoint {
   return firestore::GeoPoint(self.latitude, self.longitude);
 }