pinctrl: sh-pfc: sh73a0: Add missing TO pin to tpu4_to3 group

The tpu4_to3_mux[] array contains the TPU4TO3 pin mark, but the
tpu4_to3_pins[] array lacks the corresponding pin number.

Add the missing pin number, for non-GPIO pin F26.

Fixes: 5da4eb04 ("sh-pfc: sh73a0: Add TPU pin groups and functions")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>