iommu: Delete split_and_remove_iova()

Function split_and_remove_iova() has not been referenced since commit
e70b081c ("iommu/vt-d: Remove IOVA handling code from the non-dma_ops
path"), so delete it.

Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1607020492-189471-2-git-send-email-john.garry@huawei.com


Signed-off-by: Will Deacon <will@kernel.org>