ncpfs: fix sparse warning in ncpsign_kernel.c

We're casting anyway, might as well cast to the correct sign.
Specific to i386 (ifdef __i386__)

fs/ncpfs/ncpsign_kernel.c:58:23: warning: incorrect type in initializer (different signedness)
fs/ncpfs/ncpsign_kernel.c:58:23:    expected unsigned int *data2
fs/ncpfs/ncpsign_kernel.c:58:23:    got int *<noident>

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Petr Vandrovec <VANDROVE@vc.cvut.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>