iommu/fsl-pamu: Fix uninitialized variable warning

The variable 'i' in the function update_liodn_stash() is not
initialized and only used in a debug printk(). So it has no
meaning at all, remove it.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210415144442.25103-1-joro@8bytes.org