sparc: remove unused wp_works_ok macro

It's unused for ages, used to be required for ksyms.c back in the v1.1
times.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>