LU-17504 build: fix gcc-13 [-Werror=stringop-overread] error

LU-17504 build: fix gcc-13 [-Werror=stringop-overread] error

This patch fixes the following [-Werror=stringop-overread] and
[-Werror=attribute-warning] errors detected by gcc 13:

lustre/mgc/mgc_request.c:190:21: error: 'strcmp' reading 1 or
more bytes from a region of size 0 [-Werror=stringop-overread]
  190 | if (strcmp(logname, cld->cld_logname) == 0) {
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In function 'fortify_memcpy_chk',
    inlined from 'class_handle_ioctl' at
/root/lustre-release/lustre/obdclass/class_obd.c:381:3:
include/linux/fortify-string.h:528:25: error:
call to '__write_overflow_field' declared with attribute warning:
detected write beyond size of field (1st parameter);
maybe use struct_group()? [-Werror=attribute-warning]
  528 |  __write_overflow_field(p_size_field, size);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Jian Yu <yujian@whamcloud.com>
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I59f5a88b4cd64c9f4e67e568546baada371543b1