mt7530_pad_clk_setup() is called if port 6 is enabled. It used to do more
things than setting up port 6. That part was moved to more appropriate
locations, mt7530_setup() and mt7530_pll_setup().

Now that all it does is set up port 6, rename it to mt7530_setup_port6(),
and move it to a more appropriate location, under mt7530_mac_config().

Change mt7530_setup_port6() to void as there're no error cases.

Leave an empty mt7530_pad_clk_setup() to satisfy the pad_setup function
pointer.

This is the code path for setting up the ports before:

dsa_switch_ops :: phylink_mac_config() -> mt753x_phylink_mac_config()
-> mt753x_mac_config()
   -> mt753x_info :: mac_port_config() -> mt7530_mac_config()
      -> mt7530_setup_port5()
-> mt753x_pad_setup()
   -> mt753x_info :: pad_setup() -> mt7530_pad_clk_setup()

This is after:

dsa_switch_ops :: phylink_mac_config() -> mt753x_phylink_mac_config()
-> mt753x_mac_config()
   -> mt753x_info :: mac_port_config() -> mt7530_mac_config()
      -> mt7530_setup_port5()
      -> mt7530_setup_port6()
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-v5-4-d7d92a185cb1@arinc9.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>