alsa_sound: Configure the USB and PROXY device with proper sample rates

- For USB headset whose sample rate is other than the 8k/16k/48k
  which are supported by PROXY, ANR is observed while playback.
- getCap() function returning 0 sample rate if exact match of
  proxy supported rate is not found. This is causing device
  configuration failures in case of USB device, due to this
  playback thread closes the USB device and causes ANR.
- Fix is to configure the USB device with a sample rate supported
  by device and configure the PROXY at 48K.

CRs-Fixed: 521930
Change-Id: I8a51844d102f999618fa25f322d0ef17b38b826e