removes decoder again as there is some issue

src/iss/arch/tgc_c.h

@@ -36,7 +36,6 @@
 #include <array>
 #include <iss/arch/traits.h>
 #include <iss/arch_if.h>
-#include <iss/arch/instruction_decoder.h>
 #include <iss/vm_if.h>
 
 namespace iss {
@@ -177,8 +176,6 @@ template <> struct traits<tgc_c> {
         DII = 89,
         MAX_OPCODE
     };
-
-    static std::unique_ptr<instruction_decoder<tgc_c>> get_decoder();
 };
 
 struct tgc_c: public arch_if {