i40e: Fix uninitialized variable mfs_max

The variable mfs_max is not initialized and is being compared to find
the maximum value. Fix this by initializing it to 0.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: 90bc8e00 ("i40e: Add hardware configuration for software based DCB")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/i40e/i40e_dcb.c

@@ -1636,7 +1636,7 @@ void i40e_dcb_hw_calculate_pool_sizes(struct i40e_hw *hw,
 	u32 total_pool_size = 0;
 	int shared_pool_size; /* Need signed variable */
 	u32 port_pb_size;
-	u32 mfs_max;
+	u32 mfs_max = 0;
 	u32 pcirtt;
 	u8 i;