arm64: dts: qcom: sdm845-google: Describe Wi-Fi/BT properly

arm64: dts: qcom: sdm845-google: Describe Wi-Fi/BT properly

The onboard Wi-Fi / BT device, WCN3990, has a simple on-chip PMU, which
further spreads generated voltage. Describe the PMU in the device tree
and rewire Bluetooth and Wi-Fi supply properties to use the PMU LDO
outputs instead of referencing the SoC regulators directly.

Couldn't verify the swctrl GPIO thus omitted.

Assisted-by: Claude:claude-opus-4.6
Signed-off-by: David Heidelberg <david@ixit.cz>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260327-wcn3990-pwrctl-sdm845-v1-1-3f5c34e3fdd0@ixit.cz
Signed-off-by: Bjorn Andersson <andersson@kernel.org>