arm: Rename RdCostARM.h => RdCost_neon.cpp and simplify

This file is currently templated over `ARM_VEXT`, however in practice
this can only be set to `NEON`, and a future SVE implementation would
need other changes.

In preparation for future changes to this file, simplify it to match the
others in the `neon/` directory by moving the content to the `.cpp` file
and removing the unused `ARM_VEXT` templating.

There is no need for these functions to be members of the `RdCost`
class, so remove that, however this means that the x86 implementations
of these kernels need to become public members of the class until we can
remove the dependency on them from the Neon kernels.

Author: georges-arm

source/Lib/CommonLib/RdCost.h

@@ -148,14 +148,14 @@ class RdCost
   virtual ~RdCost();
 
   void          create( bool enableOpt = true );
+
 #if defined(TARGET_SIMD_X86)  && ENABLE_SIMD_OPT_DIST
   void          initRdCostX86();
   template <X86_VEXT vext>
   void          _initRdCostX86();
 #endif
 
 #if defined(TARGET_SIMD_ARM)  && ENABLE_SIMD_OPT_DIST
-
   void initRdCostARM();
   template<ARM_VEXT vext>
   void _initRdCostARM();
@@ -221,8 +221,7 @@ class RdCost
   static Distortion xGetSAD8          ( const DistParam& pcDtParam );
   static Distortion xGetSAD16         ( const DistParam& pcDtParam ); // needs to be public for xGetSAD_MxN_SIMD ( NOTE: they are all public in vvenc )
   static void       xGetSAD16X5       ( const DistParam& pcDtParam, Distortion* cost, bool isCalCentrePos ); // needs to be public for xGetSADX5_16xN_SIMD ( NOTE: they are all public in vvenc )
-	
-private:
+
          Distortion xGetSSE_WTD       ( const DistParam& pcDtParam ) const;
 
   static Distortion xGetSSE           ( const DistParam& pcDtParam );
@@ -274,26 +273,7 @@ class RdCost
   static Distortion xGetSADwMask_SIMD( const DistParam &pcDtParam );
 #endif
 
-#if defined(TARGET_SIMD_ARM)  && ENABLE_SIMD_OPT_DIST
-
-  template <ARM_VEXT vext>
-  static void xGetSADX5_16xN_SIMD_ARM   ( const DistParam& rcDtParam, Distortion* cost, bool isCalCentrePos );
-
-  template <ARM_VEXT vext>
-  static Distortion xGetHAD2SADs_ARMSIMD( const DistParam &rcDtParam );
-
-  template <ARM_VEXT vext, bool fastHad>
-  static Distortion xGetHADs_ARMSIMD   ( const DistParam& pcDtParam );
-
-  template<ARM_VEXT vext> 
-  static Distortion xGetSADwMask_ARMSIMD(const DistParam &rcDtParam);
-
-  template< int iWidth, ARM_VEXT vext >
-  static Distortion xGetSAD_NxN_ARMSIMD( const DistParam &rcDtParam );
-#endif
-	
   unsigned int   getBitsMultiplePredsIBC(int x, int y, bool useIMV);
-public:
 
   Distortion   getDistPart( const CPelBuf& org, const CPelBuf& cur, int bitDepth, const ComponentID compId, DFunc eDFunc, const CPelBuf* orgLuma = NULL );