sh: Fix SH-4 DMAC CHCR masking.

This patch fixes the DMA cascade by masking the correct bits.

Tested and working with Dreamcast PVR2 DMA. With this patch applied
the existing mainline code in arch/sh/drivers/dma/dma-sh.c works,
whereas before I was patching that to get round this problem.
Signed-off-by: NAdrian McMenamin <adrian@mcmen.demon.co.uk>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

include/asm-sh/cpu-sh4/dma.h

@@ -31,7 +31,7 @@
 #define TS_32		0x00000030
 #define TS_64		0x00000000
 
-#define CHCR_TS_MASK	0x30
+#define CHCR_TS_MASK	0x70
 #define CHCR_TS_SHIFT	4
 
 #define DMAOR_COD	0x00000008