sh-pfc: sh7720: Remove unused input_pu range

The PFC SH7720 SoC data contains a input_pu range used to configure
pull-up resistors using the legacy non-pinconf API. That API has been
removed from the driver, the range is thus not used anymore. Remove it.

If required, configuring pull-up resistors for the SH7720 can be
implemented using the pinconf API, as done for the SH-Mobile, R-Mobile
and R-Car platforms.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>