L2cap channel cb: Store who initiated dynamic channel

Use pL2CA_ConfigCfm_Cb to let user know the direction.

Later the user can run check in ConnectInd or ConnectCfm callback.

Bug: 159815595
Tag: #refactor
Test: compile & verify basic functions working
Change-Id: Iae663e6bea0fc9426c5dfbbfc52bd1ae848f2965