msm8660: fix getInputBufferSize to calculate buffer sizes

* dirived from alsa driver

Change-Id: Ife6dc216230617c2bc11bf6a51abe0488075acc5
msm8660: only use voip stream if sample rate is 16k or less

Change-Id: If735eee450fa9f9c99aa83c9cf1a81a955b12c57