RDMA/cxgb4: Fix warnings about casts to/from pointers of different sizes

Fix:

  drivers/infiniband/hw/cxgb4/qp.c: In function ‘create_qp’:
  drivers/infiniband/hw/cxgb4/qp.c:147: warning: cast from pointer to integer of different size
  drivers/infiniband/hw/cxgb4/qp.c: In function ‘rdma_fini’:
  drivers/infiniband/hw/cxgb4/qp.c:988: warning: cast from pointer to integer of different size
  drivers/infiniband/hw/cxgb4/qp.c: In function ‘rdma_init’:
  drivers/infiniband/hw/cxgb4/qp.c:1063: warning: cast from pointer to integer of different size
  drivers/infiniband/hw/cxgb4/mem.c: In function ‘write_adapter_mem’:
  drivers/infiniband/hw/cxgb4/mem.c:74: warning: cast from pointer to integer of different size
  drivers/infiniband/hw/cxgb4/cq.c: In function ‘destroy_cq’:
  drivers/infiniband/hw/cxgb4/cq.c:58: warning: cast from pointer to integer of different size
  drivers/infiniband/hw/cxgb4/cq.c: In function ‘create_cq’:
  drivers/infiniband/hw/cxgb4/cq.c:135: warning: cast from pointer to integer of different size
  drivers/infiniband/hw/cxgb4/cm.c: In function ‘fw6_msg’:
  drivers/infiniband/hw/cxgb4/cm.c:2326: warning: cast to pointer from integer of different size

by casting pointers to unsigned long instead of u64.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>