net: simplify eeecfg_mac_can_tx_lpi

Simplify the function.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/f9a4623b-b94c-466c-8733-62057c6d9a17@gmail.com


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