sfc: Update MCDI (firmware interface) definitions

Some commands and constants have been renamed; adjust the code
accordingly.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/mtd.c b/drivers/net/ethernet/sfc/mtd.c
index 13f61fb..7f61cd3 100644
--- a/drivers/net/ethernet/sfc/mtd.c
+++ b/drivers/net/ethernet/sfc/mtd.c
@@ -627,8 +627,7 @@
 				     struct efx_mtd *efx_mtd)
 {
 	struct efx_mtd_partition *part;
-	uint16_t fw_subtype_list[MC_CMD_GET_BOARD_CFG_OUT_FW_SUBTYPE_LIST_LEN /
-				 sizeof(uint16_t)];
+	uint16_t fw_subtype_list[MC_CMD_GET_BOARD_CFG_OUT_FW_SUBTYPE_LIST_MINNUM];
 	int rc;
 
 	rc = efx_mcdi_get_board_cfg(efx, NULL, fw_subtype_list);