dmaengine: ti-dma-crossbar: enable COMPILE_TEST

To get more coverage, enable COMPILE_TEST for this driver.
When compile testing eDMA or omap-dma, select also the ti-dma-crossbar so
it is also covered by the compile testing.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>