Fix a few warnings.

Templates shouldn't be marked as inline if they aren't defined in the header.

src/core/hle/config_mem.h

@@ -16,6 +16,6 @@
 namespace ConfigMem {
 
 template <typename T>
-inline void Read(T &var, const u32 addr);
+void Read(T &var, const u32 addr);
 
 } // namespace

src/core/hw/gpu.h

@@ -235,10 +235,10 @@ u32 GetFramebufferAddr(const u32 address);
 FramebufferLocation GetFramebufferLocation(u32 address);
 
 template <typename T>
-inline void Read(T &var, const u32 addr);
+void Read(T &var, const u32 addr);
 
 template <typename T>
-inline void Write(u32 addr, const T data);
+void Write(u32 addr, const T data);
 
 /// Update hardware
 void Update();

src/core/hw/hw.h

@@ -9,10 +9,10 @@
 namespace HW {
 
 template <typename T>
-inline void Read(T &var, const u32 addr);
+void Read(T &var, const u32 addr);
 
 template <typename T>
-inline void Write(u32 addr, const T data);
+void Write(u32 addr, const T data);
 
 /// Update hardware
 void Update();