RDMA/bnxt_re: Get the WQE index from slot index while completing the WQEs

RDMA/bnxt_re: Get the WQE index from slot index while completing the WQEs

While reporting the completions, SQ Work Queue index is required to
identify the WQE that generated the completions. In variable WQE mode, FW
returns the slot index for Error completions. Driver need to walk through
the shadow queue between the consumer index and producer index and matches
the slot index returned by FW. If a match is found, the next index of the
shadow queue is the WQE index to be considered for remaining poll_cq loop.

Link: https://patch.msgid.link/r/1724042847-1481-3-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Hongguang Gao <hongguang.gao@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>