Use 'mediatek,mt7988a' instead of 'mediatek,mt7988' as compatible
string to be in-sync with upstream and no longer break the cpufreq
driver which was also kept in sync with upstream.
Fixes: 56dd6b473b ("mediatek: sync cpufreq support with changed compatible string")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
9bc08af753