RDMA/cm: Make the local_id_table xarray non-irq

RDMA/cm: Make the local_id_table xarray non-irq

The xarray is never mutated from an IRQ handler, only from work queues
under a spinlock_irq. Thus there is no reason for it be an IRQ type
xarray.

This was copied over from the original IDR code, but the recent rework put
the xarray inside another spinlock_irq which will unbalance the unlocking.

Fixes: c206f8bad15d ("RDMA/cm: Make it clearer how concurrency works in cm_req_handler()")
Link: https://lore.kernel.org/r/0-v1-808b6da3bd3f+1857-cm_xarray_no_irq_jgg@nvidia.com
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>