sh_eth: Change platform check to CONFIG_ARCH_RENESAS

sh_eth: Change platform check to CONFIG_ARCH_RENESAS

Since commit 9b5ba0df4ea4f940 ("ARM: shmobile: Introduce ARCH_RENESAS")
is CONFIG_ARCH_RENESAS a more appropriate platform check than the legacy
CONFIG_ARCH_SHMOBILE, hence use the former.

Renesas SuperH SH-Mobile SoCs are still covered by the CONFIG_CPU_SH4
check.

This will allow to drop ARCH_SHMOBILE on ARM and ARM64 in the near
future.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>