dt-bindings: bluetooth: bring the HW description closer to reality for wcn6855

Describe the inputs from the PMU that the Bluetooth module on wcn6855
consumes and drop the ones from the host. This breaks the current
contract but the only two users of wcn6855 upstream - sc8280xp based
boards - will be updated in DTS patches sent separately while the
hci_qca driver will remain backwards compatible with older DT sources.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>