pinctrl: sh-pfc: Remove obsolete r8a7779 platform_device_id entry

Since the removal of the r8a7779 legacy SoC code in commit
c99cd90d ("ARM: shmobile: r8a7779: Remove legacy SoC code"),
r8a7779 is only supported in generic DT-only ARM multi-platform builds.
The driver doesn't need to match platform devices by name anymore, hence
remove the corresponding platform_device_id entry.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>