clk: shmobile: Remove ARCH_SHMOBILE_MULTI

As of 9b5ba0df ("ARM: shmobile: Introduce ARCH_RENESAS") all platforms
that use Renesas clock drivers now select ARCH_RENESAS. As it is present in
drivers/clk/Makefile ARCH_SHMOBILE_MULTI may now be removed.

This is part of an ongoing process to migrate from ARCH_SHMOBILE to
ARCH_RENESAS the motivation for which being that RENESAS seems to be a more
appropriate name than SHMOBILE for the majority of Renesas ARM based SoCs.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>