[PATCH] s390: test_bit return value

The test_bit function returns a non-boolean value, it returns 0,1,2,4,...
instead of only 0 or 1.  This causes wrongs results in the mincore system
call.  Check against 0 to get a proper boolean value.

Signed-off-by: Christian Borntraeger <cborntra@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>