PCI/pwrctrl: Lock device when calling device_is_bound()

PCI/pwrctrl: Lock device when calling device_is_bound()

The kerneldoc for device_is_bound() states that it must be called with
the device lock taken. Synchronize the two calls in pwrctrl core.

Fixes: b35cf3b6aa1e ("PCI/pwrctrl: Add APIs to power on/off pwrctrl devices")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20260518100700.47581-1-bartosz.golaszewski@oss.qualcomm.com