mtd: nand: rename the id field of 'struct nand_flash_dev'

The 'id' is a bit confusing name because NAND IDs are multi-byte. Re-name
it to 'dev_id' to make it clear that this is the "device ID" part (the second
byte).

While on it, clean-up the commentary for 'struct nand_flash_dev'.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index 7199acc..eb1238f 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -766,9 +766,9 @@
 	}
 
 	/* Detect how many ID bytes the NAND chip outputs */
-        for (i = 0; nand_flash_ids[i].name != NULL; i++) {
-                if (second_id_byte != nand_flash_ids[i].id)
-                        continue;
+	for (i = 0; nand_flash_ids[i].name != NULL; i++) {
+		if (second_id_byte != nand_flash_ids[i].dev_id)
+			continue;
 	}
 
 	if (ns->busw == 16)