IB/mlx4: Suppress non-fatal memory allocations

Failure in kmalloc memory allocations will throw a warning about it.
Such warnings are not needed anymore, since in commit 0ef2f05c
("IB/mlx4: Use vmalloc for WR buffers when needed"), fallback mechanism
from kmalloc() to __vmalloc() was added.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>