InitModule loads a kernel module from an ELF image. FinitModule loads a
kernel module from a file descriptor. DeleteModule unloads a kernel
module.

These syscalls require the CAP_SYS_MODULE capability.

See http://man7.org/linux/man-pages/man2/init_module.2.html and
http://man7.org/linux/man-pages/man2/delete_module.2.html for details.

Also drop deprecated syscalls related to kernel modules from the list
of unimplemented syscalls.

Change-Id: I131e17f02c5617640f5f4073982d2b27a6d78bbf
Reviewed-on: https://go-review.googlesource.com/c/144173
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>