mtd: nand: raw: rockchip_nfc: fix oobfree offset and description

The MTD framework reserves 1 or 2 bytes for the bad block marker
depending on the bus size. The rockchip_nfc driver currently only
supports a 8 bit bus, but reserves standard 2 bytes for the BBM.
The first free OOB byte is therefore OOB2 at offset 2.
Page address(PA) bytes are moved to the last 4 positions before
ECC. Update the description for U-boot.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/mtd/nand/raw/rockchip_nfc.c b/drivers/mtd/nand/raw/rockchip_nfc.c
index 25e0497..5fcf6a6 100644
--- a/drivers/mtd/nand/raw/rockchip_nfc.c
+++ b/drivers/mtd/nand/raw/rockchip_nfc.c
@@ -487,10 +487,10 @@
 		 *
 		 *    BBM  OOB1 OOB2 OOB3 |......|  PA0  PA1  PA2  PA3
 		 *
-		 * The rk_nfc_ooblayout_free() function already has reserved
-		 * these 4 bytes with:
+		 * The oobfree structure already has reserved these 4 bytes
+		 * together with 2 bytes for BBM by reducing it's length:
 		 *
-		 * oob_region->offset = NFC_SYS_DATA_SIZE + 2;
+		 * oobfree[0].length = rknand->metadata_size - NFC_SYS_DATA_SIZE - 2;
 		 */
 		if (!i)
 			memcpy(rk_nfc_oob_ptr(chip, i),
@@ -867,7 +867,7 @@
 		ecc->layout->eccpos[i] = rknand->metadata_size + i;
 
 	ecc->layout->oobfree[0].length = rknand->metadata_size - NFC_SYS_DATA_SIZE - 2;
-	ecc->layout->oobfree[0].offset = NFC_SYS_DATA_SIZE + 2;
+	ecc->layout->oobfree[0].offset = 2;
 
 	return 0;
 }