cciss: fix shadows sparse warning

Fix sparse warnings:

drivers/block/cciss.c:1591:37: warning: symbol 'i' shadows an earlier one
drivers/block/cciss.c:2437:21: warning: symbol 'i' shadows an earlier one

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Acked-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>