Remove the local declarations of the VP interface functions

There's no need to define them manually here, the normal
declarations in IWelsVP.h work just fine even if not loading
the WelsVP library dynamically.

codec/encoder/core/src/wels_preprocess.cpp

@@ -45,11 +45,6 @@
 #include "encoder_context.h"
 #include "utils.h"
 
-#ifdef NO_DYNAMIC_VP
-EResult CreateVpInterface (void** ppCtx, int iVersion);
-EResult DestroyVpInterface (void** ppCtx, int iVersion);
-#endif
-
 namespace WelsSVCEnc {
 
 #define WelsSafeDelete(p) if(p){ delete (p); (p) = NULL; }