In core function, the instances of some client resource structures are
maintained by IDR. As of kernel v6.0, IDR has been superseded by XArray
and deprecated.

This commit replaces the usage of IDR with XArray to maintain the
resource instances. The instance of XArray is allocated per client with
XA_FLAGS_ALLOC1 so that the index of allocated entry is greater than zero
and returns to user space client as handle of the resource.

Link: https://lore.kernel.org/r/20240812235210.28458-6-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>