soc: renesas: Consolidate product register handling

Currently renesas_soc_init() scans the whole device tree up to three
times, to find a device node describing a product register.
Furthermore, the product register handling for the different variants is
very similar, with the major difference being the location of the
product bitfield inside the product register.

Reduce scanning to a single pass using of_find_matching_node_and_match()
instead.  Switch to a common handling of product registers, by storing
the intrinsics of each product register type in the data field of the
corresponding match entry.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/057721f46c7499de4133135488f0f3da7fb39265.1636570669.git.geert+renesas@glider.be