lib: string_helpers: fix potential snprintf() output truncation

lib: string_helpers: fix potential snprintf() output truncation

The output of ".%03u" with the unsigned int in range [0, 4294966295] may
get truncated if the target buffer is not 12 bytes.

Link: https://lkml.kernel.org/r/20241021091417.37796-1-brgl@bgdev.pl
Fixes: 3c9f3681d0b4 ("[SCSI] lib: add generic helper to print sizes rounded to the correct SI range")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>