build/configs/esp_wrover_kit: modify readme.md
I have faced an error when tried to setup env. to build.
the 'xvjf' means that the compressed file is bzip2.
but actually the file is not bzip file. so It can show some error messages.
@@ -29,7 +29,7 @@ Get the build in binaries and libraries
[xtensa-esp32-elf-linux32-1.22.0-80-g6c4433a-5.2.0.tar.gz](https://dl.espressif.com/dl/xtensa-esp32-elf-linux32-1.22.0-80-g6c4433a-5.2.0.tar.gz)
```bash
-tar xvjf xtensa-esp32-elf-[linux*]-1.22.0-80-g6c4433a-5.2.0.tar.gz
+tar xvf xtensa-esp32-elf-[linux*]-1.22.0-80-g6c4433a-5.2.0.tar.gz
export PATH=<Your Toolchain PATH>:$PATH
```
