soundwire: Add support for 48x2 frame structure

Add support for 48x2 frame structure in soundwire
so that when slave device data path is not enabled,
all control messaging will happen with 48x2 frame.
Soundwire slave devices send an explicit request to
enable data path which in turn change the frame
structure to 48x16.

CRs-fixed: 996586
Change-Id: Ia4329ac982eb2a29a2b925897cd87ca9711c30e3
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>