pinctrl: sh-pfc: Rename .gpio_data[] to .pinmux_data[]

The sh_pfc_soc_info.gpio_data[] array contains not only GPIO data, but
also various other pinmux-related data (functions and marks).
Every single driver already calls its local array pinmux_data[].
Hence rename the sh_pfc_soc_info member to "pinmux_data".

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>