AudioPolicyManager: Add more logging for surround formats

Helpful changes for debugging the TV Surround Sound Settings:

- add a couple of ALOGV messages for get/setSurroundFormats;

- add more ALOGW for problems to setSurroundFormatEnabled;

- add dumping for APM::mSurroundFormats.

Test: check logcat and dumpsys of APM
Change-Id: Iedcdf8bc55d9c23937c1c5754dac47c37402b535