riscv: Prevent a bad reference count on CPU nodes

When populating cache leaves we previously fetched the CPU device node
at the very beginning. But when ACPI is enabled we go through a
specific branch which returns early and does not call 'of_node_put' for
the node that was acquired.

Since we are not using a CPU device node for the ACPI code anyways, we
can simply move the initialization of it just passed the ACPI block, and
we are guaranteed to have an 'of_node_put' call for the acquired node.
This prevents a bad reference count of the CPU device node.

Moreover, the previous function did not check for errors when acquiring
the device node, so a return -ENOENT has been added for that case.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Fixes: 604f32ea ("riscv: cacheinfo: initialize cacheinfo's level and  type from ACPI PPTT")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240913080053.36636-1-mikisabate@gmail.com


Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>