driver: bluetooth: hci_qca:fix unable to load the BT driver

Some modules have BT_EN enabled via a hardware pull-up,
meaning it is not defined in the DTS and is not controlled
through the power sequence. In such cases, fall through
to follow the legacy flow.

Signed-off-by: Shuai Zhang <quic_shuaz@quicinc.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>