Bluetooth: add timeout sanity check to hci_inquiry

Syzbot hit "task hung" bug in hci_req_sync(). The problem was in
unreasonable huge inquiry timeout passed from userspace.
Fix it by adding sanity check for timeout value to hci_inquiry().

Since hci_inquiry() is the only user of hci_req_sync() with user
controlled timeout value, it makes sense to check timeout value in
hci_inquiry() and don't touch hci_req_sync().

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-and-tested-by:  <syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>