pinctrl: sh-pfc: sh73a0: Use new macros for non-GPIO pins

Update the SH-Mobile AG5 pin control driver to use the new macros for
describing pins without GPIO functionality.  This replaces the use of
physical pin numbers on the SH-Mobile AG5 SoC (in 34x34 BGA package) by
symbolic enum values, referring to signal names.

Note that the user-visible names of these pins are still based on pin
numbers instead of signal names, to preserve DT backwards compatibility.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>