fix sysreg registers in RISC-V and modify the header patcher to not crash if a header doesn't include all tags of a generated .inc file

Author: moste00

arch/RISCV/RISCVInstPrinter.h

@@ -61,9 +61,4 @@ const char *getSysRegName(unsigned reg);
 
 bool isCompressed(MCInst *MI);
 
-typedef enum {
-#define GET_ENUM_VALUES_SysReg
-#include "RISCVGenCSSystemOperandsEnum.inc"
-} SysRegValue;
-
 #endif