settings: Correct Linkage member impl location

src/common/settings.cpp

@@ -151,9 +151,6 @@ float Volume() {
     return values.volume.GetValue() / static_cast<f32>(values.volume.GetDefault());
 }
 
-Linkage::Linkage(u32 initial_count) : count{initial_count} {}
-Linkage::~Linkage() = default;
-
 const char* TranslateCategory(Category category) {
     switch (category) {
     case Category::Audio:

src/common/settings_common.cpp

@@ -52,4 +52,7 @@ const std::string& BasicSetting::GetLabel() const {
     return label;
 }
 
+Linkage::Linkage(u32 initial_count) : count{initial_count} {}
+Linkage::~Linkage() = default;
+
 } // namespace Settings