r8169: remove rtl_hw_start_8168bef

We can remove rtl_hw_start_8168bef() and use rtl_hw_start_8168b()
instead because setting register Config4 is done in
rtl_jumbo_config(), being called from rtl_hw_start().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>