Bluetooth: Expose quirks through debugfs

This patch expose controller quirks through debugfs. It would be
useful for BlueZ tests using vhci. Currently there is no way to
test quirk dependent behaviour. It might be also useful for manual
testing.

Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>