staging: lustre: llite: Use kcalloc not kzalloc with mult

This patch fixes the following checkpatch.pl warnings:
WARNING: Prefer kcalloc over kzalloc with multiply
166: FILE: drivers/staging/lustre/lustre/llite/dir.c:166:
	page_pool = kzalloc(sizeof(page) * max_pages, GFP_NOFS);
796: FILE: drivers/staging/lustre/lustre/llite/lloop.c:796:
	loop_dev = kzalloc(max_loop * sizeof(*loop_dev), GFP_KERNEL);
800: FILE: drivers/staging/lustre/lustre/llite/lloop.c:800:
	disks = kzalloc(max_loop * sizeof(*disks), GFP_KERNEL);

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>