pinctrl: renesas: Rename sh_pfc_soc_operations instances

Some instances of struct sh_pfc_soc_operations are called
"<soc>_pfc_ops", others are called "<soc>_pinmux_ops" or just
"pinmux_ops".  Settle on the first variant, to avoid confusion with
"struct pinmux_ops" in the pinctrl core, and to increase consistency.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/2ab33ad1d6a20a57d16922678b78810fa55b7fc0.1640269757.git.geert+renesas@glider.be