dmaengine: ppc4xx: remove unused variable `rval'

The variable used for returning status in
`ppc440spe_adma_dma2rxor_prep_src' function is never changed
and this function just need to return 0. Thus, the `rval' can
be removed and return 0 from `ppc440spe_adma_dma2rxor_prep_src'.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Link: https://lore.kernel.org/r/20211114060856.239314-1-wangborong@cdjrlc.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/ppc4xx/adma.c

@@ -3240,7 +3240,6 @@ static int ppc440spe_adma_dma2rxor_prep_src(
 		struct ppc440spe_rxor *cursor, int index,
 		int src_cnt, u32 addr)
 {
-	int rval = 0;
 	u32 sign;
 	struct ppc440spe_adma_desc_slot *desc = hdesc;
 	int i;
@@ -3348,7 +3347,7 @@ static int ppc440spe_adma_dma2rxor_prep_src(
 		break;
 	}
 
-	return rval;
+	return 0;
 }
 
 /**