dmadev: enable build on Windows

dmadev: enable build on Windows

The dmadev library was not added to the list of libraries built on
Windows, meaning it was skipped in those builds and also that none of
the drivers were being considered for build. Adding dmadev to the list
fixes this, and also enables the skeleton dmadev driver to be built -
all-be-it with a small fix necessary.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Chengwen Feng <fengchengwen@huawei.com>
Tested-by: Conor Walsh <conor.walsh@intel.com>