nvme: fix another 32-bit build warning

The nvme_user_cmd function was recently moved around from one file
to another, which made a warning reappear that I had fixed before
at some point:

drivers/nvme/host/core.c: In function 'nvme_user_cmd':
drivers/nvme/host/core.c:424:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

This applies the same workaround that we have elsewhere in the
driver with an extra type cast to uintptr_t.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 1673f1f0 ("nvme: move block_device_operations and ns/ctrl freeing to common code")
Link: https://lkml.org/lkml/2015/10/9/611Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/nvme/host/core.c

@@ -421,7 +421,7 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 		timeout = msecs_to_jiffies(cmd.timeout_ms);
 
 	status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
-			(void __user *)cmd.addr, cmd.data_len,
+			(void __user *)(uintptr_t)cmd.addr, cmd.data_len,
 			&cmd.result, timeout);
 	if (status >= 0) {
 		if (put_user(cmd.result, &ucmd->result))