Enable new dynamic audio resampler as default

The default may still be overridden by af.resampler.quality
in the local or build properties file.  For the build properties
check the relevant device.mk files.

In the absence of being overridden, the 44.1 to 48kHz and
48 to 44.1kHz conversion will use the DYN_MED_QUALITY resamplers
and other conversion will use the DYN_LOW_QUALITY resamplers.

Change-Id: Icf9a4af5422cddc445e1904eef93984b0abe6a44
Signed-off-by: Andy Hung <hunga@google.com>