net: stmmac: simplify TX cleanup decision for ending sw LPI mode

net: stmmac: simplify TX cleanup decision for ending sw LPI mode

As mentioned in "net: stmmac: correct priv->eee_sw_timer_en setting",
we can simplify some fast-path tests.

The transmit cleaning path checks whether EEE is enabled, the transmit
path is not in LPI mode, and that we're using software timed mode.
Since the above mentioned commit, checking whether EEE is enabled is
no longer necessary as priv->eee_sw_timer_en will be false when EEE is
disabled. Simplify this test.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1tXItC-000MB6-54@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>