Add install commond in riscv gnu tools.

Cores-SweRV/demo/Readme.md

@@ -34,6 +34,12 @@ sudo make install
 ## build and install riscv tools
 
 * Opetion1 :https://github.com/riscv-collab/riscv-gnu-toolchain.git
+
+```bash
+./configure --prefix=/opt/riscv
+make linux
+```
+
 * Opetion2 :  
 
 ```bash