pinctrl: sh-pfc: r8a7795: Add support for R-Car H3 ES2.0

The Pin Function Controller module in the R-Car H3 ES2.0 differs from
ES1.x in many ways.

The goal is twofold:
  1. Support both the ES1.x and ES2.0 SoC revisions in a single binary
     for now,
  2. Make it clear which code supports ES1.x, so it can easily be
     identified and removed later, when production SoCs are deemed
     ubiquitous.

Hence this patch:
  1. Extracts the support for R-Car H3 ES1.x into a separate file, as
     the differences are quite large,
  2. Adds code for detecting the SoC revision at runtime using the new
     soc_device_match() API, and selecting pinctrl tables for the actual
     SoC revision,
  3. Replaces the core register and bitfield definitions by their
     counterparts for R-Car H3 ES2.0.

The addition of pins, groups, and functions for the various on-chip
devices is left to subsequent patches.

The R-Car H3 ES2.0 register and bitfield definitions were extracted from
a patch in the BSP by Takeshi Kihara.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Takeshi Kihara <takeshi.kihara.df@renesas.com>