Start by reading the content of the VENDOR_SPECIFIC2 register and update
each bit field based on device properties when defined.

The use of bit masks prevents fields from overriding each other and
enables users to clear bits which are set by default, like datapolarity
in this instance.
Signed-off-by: Liam Beguin <lvb@xiphos.com>
Link: https://lore.kernel.org/r/20201211191241.21306-1-liambeguin@gmail.comSigned-off-by: Vinod Koul <vkoul@kernel.org>