ion: Fix to record NR_KERNEL_MISC_RECLAIMABLE in page units

Currently NR_KERNEL_MISC_RECLAIMABLE is being updated with units of bytes.
Fix to correctly update NR_KERNEL_MISC_RECLAIMABLE using page units.

Change-Id: Ie6c620a2a2218be1b30e9f1539c9d0d92870a726
Signed-off-by: Liam Mark <lmark@codeaurora.org>