ata: sata_rcar: Remove obsolete platform_device_id entries

Since commit c99cd90d ("ARM: shmobile: r8a7779: Remove legacy
SoC code"), R-Car SoCs are 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 remaining platform_device_id
entries and platform device support.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Tejun Heo <tj@kernel.org>