编译驱动后使用insmod加载，发现有内核污染提示，网上找到了解决办法
比如：
laohu@minipc:/$ insmod /home/laohu/Downloads/mydriver/watchdog/it87_wdt.ko
..
[ 234.438784] it87_wdt: loading out-of-tree module taints kernel.
[ 234.438898] it87_wdt: module verification failed: signature and/or required key missing - tainting kernel
[ 234.440459] it87_wdt: Chip IT8786 revision 3 initialized. timeout=60 sec (nowayout=0 testmode=0)
...给ko文件添加签名
laohu@minipc:/$ sudo /usr/src/linux-4.19.83/scripts/sign-file sha512 /usr/src/linux-4.19.83/certs/signing_key.pem /usr/src/linux-4.19.83/certs/signing_key.x509 /home/laohu/Downloads/mydriver/watchdog/it87_wdt.ko