RDMA/rxe: Return the correct errno

RDMA/rxe: Return the correct errno

In the function __rxe_add_to_pool, the function xa_alloc_cyclic is
called. The return value of the function xa_alloc_cyclic is as below:
"
 Return: 0 if the allocation succeeded without wrapping.  1 if the
 allocation succeeded after wrapping, -ENOMEM if memory could not be
 allocated or -EBUSY if there are no free entries in @limit.
"
But now the function __rxe_add_to_pool only returns -EINVAL. All the
returned error value should be returned to the caller.

Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Link: https://lore.kernel.org/r/20240408142142.792413-1-yanjun.zhu@linux.dev
Signed-off-by: Leon Romanovsky <leon@kernel.org>