[PATCH] s390: remove one set of brackets in __constant_test_bit()

Right now in __constant_test_bit for the s390 there is an extra set of ()
surrounding the calculation.  This patch simply removes one set of () that is
surrounding the whole clause.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>