cxl: Simplify cxl_rd_ops allocation and handling

cxl: Simplify cxl_rd_ops allocation and handling

A root decoder's callback handlers are collected in struct cxl_rd_ops.
The structure is dynamically allocated, though it contains only a few
pointers in it. This also requires to check two pointes to check for
the existence of a callback.

Simplify the allocation, release and handler check by embedding the
ops statically in struct cxl_root_decoder.

Implementation is equivalent to how struct cxl_root_ops handles the
callbacks.

[ dj: Fix spelling error in commit log. ]

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
Link: https://patch.msgid.link/20251114075844.1315805-2-rrichter@amd.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>