dts64: mt7622: enable all pwm for bananapi r64

mt7622 only supports 6 pwm-channels so drop pwm7

third pwm (pwm2) is inverted and connected to fan-socket

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Link: https://lore.kernel.org/r/20201016204019.2606-2-linux@fw-web.de


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>