ci: check correct gcc name

Signed-off-by: Huaqi Fang <[email protected]>

.gitlab-ci.yml

@@ -53,7 +53,7 @@ stages:
     - apt install -y python3 make python3-pip
     - pip3 config set global.index-url https://pypi.tuna.tsinghua.edu.cn/simple
     - python3 -m pip install --upgrade pip
-    - which riscv-nuclei-elf-gcc && riscv-nuclei-elf-gcc --version
+    - which riscv64-unknown-elf-gcc && riscv64-unknown-elf-gcc --version
     - which make && make --version
     - which python3 && python3 --version
     # prepare nuclei_sdk and set environment variable NUCLEI_SDK_ROOT