hal: Remove in_get_stream and out_get_stream

Remove in_get_stream and out_get_stream and
add in_ctxt and out_ctxt members to stream_in/out
structs to track and directly access stream contexts.
Mitigate race conditions with the active_in/outputs_list
when in/out_get_stream reads the list.

Change-Id: Iefc77d3c862b16dce8086e1afba15cf0210155b4