arm64: renesas: Remove the ARCH_SHMOBILE Kconfig symbol

The Kconfig symbol for Renesas 64-bit ARM SoCs has always been
ARCH_RENESAS, with ARCH_SHMOBILE being selected to reuse drivers shared
with Renesas 32-bit ARM and/or Renesas SuperH SH-Mobile SoCs.

Commit 9b5ba0df ("ARM: shmobile: Introduce ARCH_RENESAS")
started the conversion from ARCH_SHMOBILE to ARCH_RENESAS for Renesas
32-bit SoCs.  Now all drivers for Renesas ARM SoCs have gained proper
ARCH_RENESAS platform dependencies, there is no longer a need to select
ARCH_SHMOBILE.

With ARCH_SHMOBILE gone, move the ARCH_RENESAS section up, to restore
alphabetical sort order.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>