pinctrl: single: use of_device_get_match_data() to get soc data

Use of_device_get_match_data() instead of of_match_device().
It allows us to remove the forward declaration of pcs_of_match.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>