audioflinger: Extend debug logs in RecordThread

This seems to be helpful to figure out why requesting
low latency recording fails. E.g. it can fail because
RecordThread just doesn't enable fast capture, or because
pipe memory allocation has failed, or due to parameters
incompatibility.

Change-Id: Ia5122b0591836c4999e73f3460c761484f5c2859
Test: manual