Bluetooth: Fix regression with incoming L2CAP connections

PTS test A2DP/SRC/SRC_SET/TC_SRC_SET_BV_02_I revealed that
( probably after the df3c3931 commit ) the l2cap connection
could not be established in case when the "Auth Complete" HCI
event does not arive before the initiator send "Configuration
request", in which case l2cap replies with "Command rejected"
since the channel is still in BT_CONNECT2 state.

Based on patch from: Ilia Kolomisnky <iliak@ti.com>

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>