Bluetooth: controller: Fix aux scanning for connectable ADV_EXT_IND

When in initiating state we need to handle ADV_EXT_IND as in regular
scan sice we always want to scan AUX_ADV_IND in order to be able to
connect.

Signed-off-by: Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>