[MTD] Define and use MTD_FAIL_ADDR_UNKNOWN instead of 0xffffffff

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index d1129ba..5822805 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2042,7 +2042,7 @@
 		return -EINVAL;
 	}
 
-	instr->fail_addr = 0xffffffff;
+	instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 
 	/* Grab the lock and see if the device is available */
 	nand_get_device(chip, mtd, FL_ERASING);