hal: HDMI samplerate correction for DDP-DD passthru

-for DDP content HDMI sample rate is determined by multiplying
the content rate with four. But it should be avoided for DDP to DD
converter case.
-extending the buffer size to store wav header info. This is needed
for wave-extensible format.

Change-Id: Idbab1bb1551fa4c4531abfd62473b5e219377512