RDMA/bnxt_re: Initialize opcode while sending message

Fix compilation warning:

drivers/infiniband/hw/bnxt_re/qplib_rcfw.c:325:18:
  error: variable 'opcode' is uninitialized when used here [-Werror,-Wuninitialized]
        crsqe->opcode = opcode;
                        ^~~~~~
drivers/infiniband/hw/bnxt_re/qplib_rcfw.c:291:11:
  note: initialize the variable 'opcode' to silence this warning
        u8 opcode;
                 ^
                  = '\0'

Fixes: bcfee4ce ("RDMA/bnxt_re: remove redundant cmdq_bitmap")
Link: https://lore.kernel.org/r/6ad1e44be2b560986da6fdc6b68da606413e9026.1686644105.git.leonro@nvidia.com


Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>