staging: lustre: lnet: prefer kcalloc over kzalloc with multiply

Use kcalloc for allocating an array instead of kzalloc with
multiply. kcalloc is the preferred API. Issue reported by
checkpatch.pl

Signed-off-by: Sumit Pundir <pundirsumit11@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>