umem: remove redundant initialization of variable ret

The variable ret is being initialized with a value that is never read
and it is being updated later with a new value.  The initialization is
redundant and can be removed.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Addresses-Coverity: ("Unused value")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/umem.c

@@ -784,7 +784,7 @@ static const struct block_device_operations mm_fops = {
 
 static int mm_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
-	int ret = -ENODEV;
+	int ret;
 	struct cardinfo *card = &cards[num_cards];
 	unsigned char	mem_present;
 	unsigned char	batt_status;