Fix index regression in nand_read_subpage

Commit 7351d3a5dbf42ba3299af71db3296be447bc1516 added an index variable
as part of fixing checkpatch warnings, presumably as a tool to make some
long lines shorter, however it only set that index in the case of there
being no gaps in eccpos for the fragment being read.  Which means the
later step of filling ecccode from oob_poi will use the wrong indexing
into eccpos in that case.

This patch restores the behaviour that existed prior to that change.

Signed-off-by: Ron Lee <ron@debian.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/nand_base.c

@@ -1174,13 +1174,14 @@ static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
 	int data_col_addr, i, gaps = 0;
 	int datafrag_len, eccfrag_len, aligned_len, aligned_pos;
 	int busw = (chip->options & NAND_BUSWIDTH_16) ? 2 : 1;
-	int index = 0;
+	int index;
 	unsigned int max_bitflips = 0;
 
 	/* Column address within the page aligned to ECC size (256bytes) */
 	start_step = data_offs / chip->ecc.size;
 	end_step = (data_offs + readlen - 1) / chip->ecc.size;
 	num_steps = end_step - start_step + 1;
+	index = start_step * chip->ecc.bytes;
 
 	/* Data size aligned to ECC ecc.size */
 	datafrag_len = num_steps * chip->ecc.size;
@@ -1217,8 +1218,6 @@ static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
 		 * Send the command to read the particular ECC bytes take care
 		 * about buswidth alignment in read_buf.
 		 */
-		index = start_step * chip->ecc.bytes;
-
 		aligned_pos = eccpos[index] & ~(busw - 1);
 		aligned_len = eccfrag_len;
 		if (eccpos[index] & (busw - 1))