soundwire: Add support for soundwire bulk write

Soundwire supports bulk register writes to write
multiple registers in one transaction. Change adds
support in soundwire framework to allow multiple
register writes in one transaction.

Change-Id: Icaa845e34b93af268c73a35fa70697a179aa6584
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>