pinctrl: sh-pfc: r8a7795: Add pinmux data for single-function pins

Pins that (1) can be configured as either GPIO or a single peripheral
function, and (2) that don't need configuration in an IPSRx register,
should still be listed in the pinmux_data[] array.

Else selecting the peripheral function fails with e.g.:

    sh-pfc e6060000.pfc: cannot locate data/mark enum_id for mark 1281

(mark 1281 is MSIOF0_SCK_MARK).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>