Support MP2 contents in AVI container.

In present code only "Wave Format = 0x55 (MPEG Layer 3)" is supported in AVI container.
With this fix, adding support for "Wave Format = 0x50 (MPEG)".
As per "RFC 2361 - WAVE and AVI Codec Registries":
A.45 MPEG
WAVE form Registration Number (hex): 0x0050
Codec ID in the IANA Namespace:      audio/vnd.wave;codec=50
WAVE form wFormatTag ID:             WAVE_FORMAT_MPEG

Change-Id: I7cc9d3c8bd8da7a079ac8d50a6d61ccbdedb6f82
Signed-off-by: gbhakteX <gurudattax.bhakte@intel.com>