add isa string parser for smstateen

riscv/isa_parser.cc

@@ -164,6 +164,8 @@ isa_parser_t::isa_parser_t(const char* str, const char *priv)
     } else if (ext_str == "zkr") {
       extension_table[EXT_ZKR] = true;
     } else if (ext_str == "zkt") {
+    } else if (ext_str == "smstateen") {
+      extension_table[EXT_SMSTATEEN] = true;
     } else if (ext_str == "svnapot") {
       extension_table[EXT_SVNAPOT] = true;
     } else if (ext_str == "svpbmt") {

riscv/isa_parser.h

@@ -31,6 +31,7 @@ typedef enum {
   EXT_ZBPBO,
   EXT_ZPN,
   EXT_ZPSFOPERAND,
+  EXT_SMSTATEEN,
   EXT_SVNAPOT,
   EXT_SVPBMT,
   EXT_SVINVAL,