Bluetooth: Use BIT(n) macro instead of manually encoding (1 << n)

The flags for the management command table used manual encoding of
bits in the form of (1 << n). It is however preferred to use BIT(n)
macro instead.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>