staging: r8188eu: remove rtw_ioctl function

staging: r8188eu: remove rtw_ioctl function

Remove rtw_ioctl function from os_dep/ioctl_linux.c, its declaration
in include/osdep_intf.h, and finally its inclusion as the value of the
.ndo_do_ioctl member of struct net_device_ops rtw_netdev_ops in
os_dep/os_intfs.c.

The e-mail from Arnd Bergmann at:
https://lore.kernel.org/linux-next/CAK8P3a0WRMNmBmBDerZ0nWPdFZKALnxrj-uUFBkTP-MOtv48vg@mail.gmail.com
explains the justification for this approach. Essentially, changes from
net-next make the existing function and its use of SIOCDEVPRIVATE ioctls
unworkable without changes.

Functions called from rtw_ioctl that are now no longer accessible will
be cleaned up in further patches. Additionally, once these changes have
made their way downstream to the staging branch, we can modify and
reconnect rtw_android_priv_cmd via ndo_siocdevprivate in struct
net_device_ops.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210810074504.957-1-phil@philpotter.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>