openrisc: Refactor struct cpuinfo_or1k to reduce duplication

The "cpuinfo_or1k" structure currently has identical data members for
different cache components.

Remove these fields out of struct cpuinfo_or1k and into its own struct.
This reduces duplication while keeping cpuinfo_or1k extensible so more
cache descriptors can be added in the future.

Also add a new field "sets" to the new structure.

Signed-off-by: Sahil Siddiq <sahilcdq0@gmail.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>