block: don't use strcpy to copy blockdev name

block: don't use strcpy to copy blockdev name

0-day bot flagged the use of strcpy() in blk_trace_setup(), because the
source buffer can theoretically be bigger than the destination buffer.

While none of the current callers pass a string bigger than
BLKTRACE_BDEV_SIZE, use strscpy() to prevent eventual future misuse and
silence the checker warnings.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202602020718.GUEIRyG9-lkp@intel.com/
Fixes: 113cbd62824a ("blktrace: pass blk_user_trace2 to setup functions")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>