mt76: mt7921: wake the device before dumping power table

Always wake the device up before dumping the single_sku power table
otherwise the device can hang.

Fixes: ea29acc9 ("mt76: mt7921: add dumping Tx power table")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>