sys/sys/kernel.h: Remove intermediate type casting

[zlei]

Summary

The type of sysinit's member udata is const void *, it is perfect valid to do implicit type casting from other pointer types, so no need for the intermediate type casting to void *.

MFC after: 1 week

[kib]

For the udata part, I agree.

For the func, IMO the goal of changes, if any, should be the removal of any casts. Perhaps consumers should explicitly use C_SYSINIT if they need a const arg.

[zlei]

Remove only for the udata right now, to move fast.

[zlei]

sys/sys/kernel.h

298

Ah, I see why this casting.

From the comments above,

The casts are necessary to have the compiler produce the correct warnings when -Wcast-qual is used.

Well, this will catch mistake like the following one, the func is type void (*)(char *) but the udata is type const char *. The casting to void * is intentional, so that SYSINIT accept only non-const multiplexer.