w1: fix for loop in w1_f29_remove_slave()

The for loop was looking for i <= 0 instead of i >= 0 so this function
never did anything.  Also we started with i = NB_SYSFS_BIN_FILES instead
of "NB_SYSFS_BIN_FILES - 1" which is an off by one bug.

Reported-by: Bojan Prtvar <prtvar.b@gmail.com>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Jean-Franois Dagenais <dagenaisj@sonatest.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>