RDMA/core: Add necessary spaces

Space is required before '(' of switch statements and around '='.

Link: https://lore.kernel.org/r/1617783353-48249-4-git-send-email-liweihang@huawei.com


Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>