Use coccinell to detect wrong code patterns in CI/CD

[masatake]

https://www.kernel.org/doc/html/v4.18/dev-tools/coccinelle.html

An example of wrong code patter was reported in 8fffa20

[b4n]

A quick look didn't make me understand how we'd use this, but if it is able to catch calls with improper types, that'd be awesome indeed :)
There are probably more tricky cases like this (where there is a cast making things look explicit and good, but the cast is actually wrong), or even worse this (where the incorrect cast is valid, implicit, and doubly indirect (through a variable and intermediate function calls)), that I'm not sure any tool would be able to catch though… even a compiler plugin would require not only check the call, but the whole call chain to figure out there's a char to int cast in the value at some level.