Customize clang-format coding styles for C source files based on Mozilla template.
To check whether the C source codes are well formatted:
``` bash
$ cd ${wamr-root}
$ clang-format --Werror --dry-run --style=file path/to/file
```
To format the C source codes in place
``` bash
$ cd ${wamr_root}
$ clang-format -i --style=file path/to/file
```
Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>
