rtl8192e: use HAVE_NET_DEVICE_OPS unconditionally

Mainline provides NET_DEVICE_OPS, remove alternate code paths and now
obsolete defines from ccflags-y.

Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>