Bluetooth: hci_bcm: Prepare PM runtime support

Change some CONFIG_PM_SLEEP to CONFIG_PM as hu and is_suspended parameters
will be used during PM runtime callbacks.

Add bcm_suspend_device() and bcm_resume_device() which performs link
management for PM callbacks.
These functions will be used for runtime management.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>