staging: r8188eu: remove include/autoconf.h

No one uses this file, so just remove it.

Also remove the pointless Makefile rule that was attempting to create
it.

Link: https://lore.kernel.org/r/20210730092417.1014392-5-gregkh@linuxfoundation.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>