i40e: fix an uninitialized variable bug

We removed this initialization but it is required.  Let's put it back.

Fixes: 895106a5 ('i40e: trivial fixes')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_hmc.c

@@ -49,7 +49,7 @@ i40e_status i40e_add_sd_table_entry(struct i40e_hw *hw,
 	struct i40e_hmc_sd_entry *sd_entry;
 	bool dma_mem_alloc_done = false;
 	struct i40e_dma_mem mem;
-	i40e_status ret_code;
+	i40e_status ret_code = I40E_SUCCESS;
 	u64 alloc_len;
 
 	if (NULL == hmc_info->sd_table.sd_entry) {