pinctrl: sh-pfc: r8a7794: Remove reserved bits

The R8A7794 PFC driver was apparently based on the preliminary revisions
of the user's manual which had some signals and MOD_SEL register fields
described which the recent manual changed to reserved. Of course, these
signals haven't ever been really used, which makes removing them
painless.

While at it, make the large *enum* look better by starting a new line
each time a new row in the IPSR and MOD_SEL register field tables is
started.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>