[libata] sata_dwc_460ex: signdness bug

dma_dwc_xfer_setup() returns an int and "dma_chan" needs to be signed
for the error handling to work.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
1 file changed