sockit: add support for ssm2603 audio interface

The ssm2603 chip has two interfaces, an i2c interface for
control and an i2s interface for the actual data.
This connects both of those interfaces.
However, only the tx side of the i2s interface is currently
connected.
sockit: assign vga irq
wb_bfm: make Tp an external parameter and default to 0
wb_bfm: fix classic cycle accesses

Use the next task, common with burst accesses, instead of the
non-functional wait_for_ack task to wait for acks.
Also, completely remove the non-functional wait_for_ack task.