SoundPool.Builder: document default values
SoundPool.Builder: document default values

Complete javadoc for android.media.SoundPool.Builder to document
 what the default values are.

Bug 17059255

Change-Id: I966e9ed00ed75a78c9b4741b7f68bae996442cdf

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base