ARM: rmobile: Zap CONFIG_MMC_RENESAS_TUNING

Drop the CONFIG_MMC_RENESAS_TUNING symbol from Gen3 configs.
This symbol is no longer used after the Matsushita SDHI driver,
instead the renesas-sdhi driver uses CONFIG_MMC_HS200_SUPPORT
to discern whether the tuning support should be compiled in.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
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V2: Submit this on top of configs which are actually in mainline