sh-pfc: r8a7791: Fix definition of MOD_SEL3

There is a missing 0 entry from the MOD_SEL3 table.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>