Remove inaccurate compatible string 'mediatek,mt7986-ethsys' which
results in the wrong clock driver probing on MT7981 with Linux 6.1 and
ends up freezing the system once WED is used.
Fixes: da970d63fb ("mediatek: switch to Linux version 6.1")
Reported-by: Chen Minqiang <ptpt52@gmail.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>