nvme-pci: code cleanup for nvme_alloc_host_mem()

Although use of for loop is preferred it is not a common practice to
have 80 char long for loop initialization and comparison section.

Use temp variables for calculating values and replace them in the
for loop with size of all variables to set to u64 since preferred
variable is declared as u64.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/pci.c

@@ -1933,12 +1933,12 @@ out:
 
 static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)
 {
-	u32 chunk_size;
+	u64 min_chunk = min_t(u64, preferred, PAGE_SIZE * MAX_ORDER_NR_PAGES);
+	u64 hmminds = max_t(u32, dev->ctrl.hmminds * 4096, PAGE_SIZE * 2);
+	u64 chunk_size;
 
 	/* start big and work our way down */
-	for (chunk_size = min_t(u64, preferred, PAGE_SIZE * MAX_ORDER_NR_PAGES);
-	     chunk_size >= max_t(u32, dev->ctrl.hmminds * 4096, PAGE_SIZE * 2);
-	     chunk_size /= 2) {
+	for (chunk_size = min_chunk; chunk_size >= hmminds; chunk_size /= 2) {
 		if (!__nvme_alloc_host_mem(dev, preferred, chunk_size)) {
 			if (!min || dev->host_mem_size >= min)
 				return 0;