hvsock: remove useless casts, checks & functions

[freebsd_igalic.co]

Summary

This is a copy of a copy of a pre-C89 pattern.
We don't need the casts, so remove the helper macros as well.
While here, remove a function that is now recognized as unused.

Sponsored by: The FreeBSD Foundation

[glebius]

Looks like this socket has special handling of so_pcb. While it is allocated in pr_attach, like all others do, it has two paths for deallocation - for listening socket it is normal pr_detach, but it also may be deallocated at device detach method.

I'd suggest to split this changeset into 3 separate parts, which actually are unrelated:

• Remove useless SOCK_STREAM checks
• Remove useless casts of so_pcb
• Investigate what's going on with so_pcb and are those checks needed or not? If they are, why this socket is designed so different to normal?

[kevans]

I'd add whu@ on these reviews as well, for hvsock in particular

[freebsd_igalic.co]

In D44520#1015375, @glebius wrote:

…
I'd suggest to split this changeset into 3 separate parts, which actually are unrelated:

• Remove useless SOCK_STREAM checks
• Remove useless casts of so_pcb

I can do these two by myself, but I will need @whu's input on this:

• Investigate what's going on with so_pcb and are those checks needed or not? If they are, why this socket is designed so different to normal?