pinctrl: visconti: PINCTRL_TMPV7700 should depend on ARCH_VISCONTI

The Toshiba Visconti TMPV7700 series pin controller is only present on
Visconti SoCs.  Hence add a dependency on ARCH_VISCONTI, to prevent
asking the user about this driver when configuring a kernel without
Visconti platform support.

Fixes: a68a7844 ("pinctrl: visconti: Add Toshiba Visconti SoCs pinctrl support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Link: https://lore.kernel.org/r/20201005125049.26926-1-geert+renesas@glider.be


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>