staging: rtlwifi: use siocdevprivate

rtl8188eu has an "android private" ioctl command multiplexer
that is not currently safe for use in compat mode because
of its triple-indirect pointer.

rtl8723bs uses a different interface on the SIOCDEVPRIVATE
command, based on the iwpriv data structure

Both also have normal unreachable iwpriv commands, and all
of the above should probably just get removed. For the
moment, just switch over to the new interface.

Cc: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>