Fix whitespace
Avoid some function pointer casts

This casts allow to pass function with wrong signatures, without the
compiler noticing it.

In case of the SPI stack and RS485 stack the dispatch functions had the
wrong return type, void instead of int.
Don't enable RED Brick support by default
red-stack: Use EVENT_PRIO | EVENT_ERROR instead of EPOLLPRI | EPOLLERR
red-stack: Properly ignore read return value