RDMA/erdma: Eliminate unnecessary casting for erdma_post_cmd_wait

erdma_post_cmd_wait does not use the 'u64 *req' input parameter directly.
So it is better to define it to 'void *req', and by this we can eliminate
the casting when calling erdma_post_cmd_wait.

Signed-off-by: Cheng Xu <chengyou@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220909093822.33868-2-chengyou@linux.alibaba.com


Signed-off-by: Leon Romanovsky <leon@kernel.org>