net/mlx4: Address build warnings on set but not used variables

Handle the compiler warnings on variables which are set but not used
by removing the relevant variable or casting a return value which is
ignored on purpose to void.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
5 files changed