sfc: mtd: Use MTD_FAIL_ADDR_UNKNOWN instead of 0xffffffff

As of bb0eb217, MTD_FAIL_ADDR_UNKNOWN should be used to indicate mtd
erase failure not specific to any particular block.

Use MTD_FAIL_ADDR_UNKNOWN instead of 0xffffffff when setting
'erase->fail_addr' in 'efx_mtd_erase()'.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/net/ethernet/sfc/mtd.c

@@ -193,7 +193,7 @@ static int efx_mtd_erase(struct mtd_info *mtd, struct erase_info *erase)
 		erase->state = MTD_ERASE_DONE;
 	} else {
 		erase->state = MTD_ERASE_FAILED;
-		erase->fail_addr = 0xffffffff;
+		erase->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 	}
 	mtd_erase_callback(erase);
 	return rc;