The pad_setup function pointer was introduced with 88bdef8b ("net: dsa:
mt7530: Extend device data ready for adding a new hardware"). It was being
used to set up the core clock and port 6 of the MT7530 switch, and pll of
the MT7531 switch.

All of these were moved to more appropriate locations, and it was never
used for the switch on the MT7988 SoC. Therefore, this function pointer
hasn't got a use anymore. Remove it.
Acked-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Link: https://lore.kernel.org/r/20240206-for-netnext-mt7530-improvements-2-v5-5-d7d92a185cb1@arinc9.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>