The printf API has a much richer support for various format
specifiers. Switch the Bluetooth logging macros to use printf instead
of printk and make sure STDOUT_CONSOLE gets selected when
BLUETOOTH_DEBUG is selected (so printf actually works).
Change-Id: I9a9818d51a677c6c79a35fef6daca7979f61c78d
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>