mtd: rawnand: marvell: prevent harmless warnings

Since the addition of WARN_ON() in nand_subop_get_data/addr_len()
helpers, this driver will produce harmless warnings (mostly at probe)
just because it always calls the nand_subop_get_data_len() helper in
the parsing function (even on non-data instructions, where this value
is meaningless and unneeded).

Fix these warnings by deriving the length only when it is relevant.

Fixes: 760c435 ("mtd: rawnand: make subop helpers return unsigned values")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

drivers/mtd/nand/raw/marvell_nand.c

@@ -1547,7 +1547,7 @@ static void marvell_nfc_parse_instructions(struct nand_chip *chip,
 	for (op_id = 0; op_id < subop->ninstrs; op_id++) {
 		unsigned int offset, naddrs;
 		const u8 *addrs;
-		int len = nand_subop_get_data_len(subop, op_id);
+		int len;
 
 		instr = &subop->instrs[op_id];
 
@@ -1593,6 +1593,7 @@ static void marvell_nfc_parse_instructions(struct nand_chip *chip,
 				nfc_op->ndcb[0] |=
 					NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW) |
 					NDCB0_LEN_OVRD;
+				len = nand_subop_get_data_len(subop, op_id);
 				nfc_op->ndcb[3] |= round_up(len, FIFO_DEPTH);
 			}
 			nfc_op->data_delay_ns = instr->delay_ns;
@@ -1606,6 +1607,7 @@ static void marvell_nfc_parse_instructions(struct nand_chip *chip,
 				nfc_op->ndcb[0] |=
 					NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW) |
 					NDCB0_LEN_OVRD;
+				len = nand_subop_get_data_len(subop, op_id);
 				nfc_op->ndcb[3] |= round_up(len, FIFO_DEPTH);
 			}
 			nfc_op->data_delay_ns = instr->delay_ns;