With modern GCC, we get warnings such as:
cmd/jffs2.c: In function 'mtdparts_init':
arch/sh/include/asm/string.h:110:38:
warning: array subscript is above array bounds [-Warray-bounds]
   : "0" (__cs), "1" (__ct), "r" (__cs+__n)
                                  ~~~~^~~~

This results in a small size reduction as well.

Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Tom Rini <trini@konsulko.com>