cpumask: Omit terminating null byte in cpumap_print_{list,bitmask}_to_buf

cpumask: Omit terminating null byte in cpumap_print_{list,bitmask}_to_buf

The changes in the patch series [1] introduced a terminating null byte
when reading from cpulist or cpumap sysfs files, for example:

  $ xxd /sys/devices/system/node/node0/cpulist
  00000000: 302d 310a 00                             0-1..

Before this change, the output looked as follows:

  $ xxd /sys/devices/system/node/node0/cpulist
  00000000: 302d 310a                                0-1.

Fix this regression by excluding the terminating null byte from the
returned length in cpumap_print_list_to_buf and
cpumap_print_bitmask_to_buf.

[1] https://lore.kernel.org/all/20210806110251.560-1-song.bao.hua@hisilicon.com/

Fixes: 4654a45d1895 ("cpumask: introduce cpumap_print_list/bitmask_to_buf to support large bitmask and list")
Acked-by: Barry Song <song.bao.hua@hisilicon.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20210916222705.13554-1-tklauser@distanz.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>