net/mlx4: Fix UBSAN warning of signed integer overflow

UBSAN: Undefined behavior in
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:626:29
signed integer overflow: 1802201963 + 1802201963 cannot be represented
in type 'int'

The union of res_reserved and res_port_rsvd[MLX4_MAX_PORTS] monitors
granting of reserved resources. The grant operation is calculated and
protected, thus both members of the union cannot be negative.  Changed
type of res_reserved and of res_port_rsvd[MLX4_MAX_PORTS] from signed
int to unsigned int, allowing large value.

Fixes: 5a0d0a6161ae ("mlx4: Structures and init/teardown for VF resource quotas")
Signed-off-by: Aya Levin <ayal@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/mlx4.h

@@ -540,8 +540,8 @@ struct slave_list {
 struct resource_allocator {
 	spinlock_t alloc_lock; /* protect quotas */
 	union {
-		int res_reserved;
-		int res_port_rsvd[MLX4_MAX_PORTS];
+		unsigned int res_reserved;
+		unsigned int res_port_rsvd[MLX4_MAX_PORTS];
 	};
 	union {
 		int res_free;