staging: r8188eu: Remove some dead code from headers

The headers for this driver contain a number of unused structs and macros
that are removed. File include/ioctl_cfg80211.h is now empty and was
deleted.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>