mmc: atmel-mci: use ATMEL_PDC_SCND_BUF_OFF instead of a literal value

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/include/linux/atmel_pdc.h b/include/linux/atmel_pdc.h
index 5058a31..63499ce 100644
--- a/include/linux/atmel_pdc.h
+++ b/include/linux/atmel_pdc.h
@@ -33,4 +33,6 @@
 
 #define ATMEL_PDC_PTSR		0x124	/* Transfer Status Register */
 
+#define ATMEL_PDC_SCND_BUF_OFF	0x10	/* Offset between first and second buffer registers */
+
 #endif