net: stmmac: remove old EEE methods

As we no longer call the set_eee_mode(), reset_eee_mode() and
set_eee_lpi_entry_timer() methods, remove these and their glue in
common.h

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1tffe7-003ZIm-Qv@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>