pinctrl: sh-pfc: r8a77990: Rename IOCTRLx registers

The R-Car Gen3 HardWare Manual Errata for Rev. 1.00 (Jul 2, 2018)
renamed the various miscellaneous I/O control registers (IOCTRLx) on
R-Car E3, to reflect better their actual purposes, and matching other
SoCs.

Update the code to match this.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>