adds the missing vector csrs to the architectural state

src/iss/arch/tgc5c.h

@@ -256,6 +256,10 @@ struct tgc5c: public arch_if {
     void set_vstart(uint32_t val){}
     uint32_t get_vl(){return 0;}
     uint32_t get_vtype(){return 0;}
+    uint32_t get_vxsat(){return 0;}
+    void set_vxsat(uint32_t val){}
+    uint32_t get_vxrm(){return 0;}
+    void set_vxrm(uint32_t val){}
 
 };