dmaengine: ioat: remove unused declarations in dma.h

ioat_ring_alloc_order and ioat_ring_max_alloc_order have
been removed since commit cd60cd96 ("dmaengine: IOATDMA:
Removing descriptor ring reshape"), so remove them.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20220911091817.3214271-1-cuigaosheng1@huawei.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>