RDMA/erdma: Refactor the initialization and destruction of EQ

We extracted the common parts of the initialization/destruction
process to make the code cleaner.

Signed-off-by: Cheng Xu <chengyou@linux.alibaba.com>
Link: https://patch.msgid.link/20240902112920.58749-2-chengyou@linux.alibaba.com


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