Bluetooth: Fix hci_inquiry ioctl usage

Since the HCI request framework was properly fixed, the hci_req_sync
call, in hci_inquiry, will return as soon as the HCI command completes
(not the Inquiry procedure). However, in inquiry ioctl implementation,
we want to sleep the user process until the inquiry procedure finishes.

This patch changes hci_inquiry so, in case the HCI Inquiry command
was executed successfully, it waits the HCI_INQUIRY flag to be cleared.
This way, the user process will sleep until the inquiry procedure
finishes.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>