dmaengine: idxd: set defaults for wq configs

Add default values for wq size, max_xfer_size and max_batch_size. These
values should provide a general guidance for the wq configuration when
the user does not specify any specific values.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163528473483.3926048.7950067926287180976.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>