net: encx24j600: convert to use maple tree register cache

The maple tree register cache is based on a much more modern data structure
than the rbtree cache and makes optimisation choices which are probably
more appropriate for modern systems than those made by the rbtree cache.

Signed-off-by: Bo Liu <liubo03@inspur.com>
Link: https://lore.kernel.org/r/20240202064336.39138-1-liubo03@inspur.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>