staging: r8188eu: remove ip.h header file

staging: r8188eu: remove ip.h header file

The struct ip_options declared in ip.h is only unsed in the optlength
macro which is also defined in ip.h and not used in the driver code.
All other definitions/declarations in ip.h are duplicated from
<include/uapi/linux/ip.h>. Remove the ip.h header file and its includes.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210824123621.10801-3-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>