nvme-pci: use the consistent return type of nvme_pci_iod_alloc_size()

The nvme_pci_iod_alloc_size() should return 'size_t' type to be
consistent with the sizeof return value.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/pci.c

@@ -362,7 +362,7 @@ static int nvme_pci_npages_sgl(unsigned int num_seg)
 	return DIV_ROUND_UP(num_seg * sizeof(struct nvme_sgl_desc), PAGE_SIZE);
 }
 
-static unsigned int nvme_pci_iod_alloc_size(struct nvme_dev *dev,
+static size_t nvme_pci_iod_alloc_size(struct nvme_dev *dev,
 		unsigned int size, unsigned int nseg, bool use_sgl)
 {
 	size_t alloc_size;