mtd: nand: rename NAND_USE_FLASH_BBT

Recall the recently added prefix requirements:
 * "NAND_" for flags in nand.h, used in nand_chip.options
 * "NAND_BBT_" for flags in bbm.h, used in nand_chip.bbt_options
        or in nand_bbt_descr.options

Thus, I am changing NAND_USE_FLASH_BBT to NAND_BBT_USE_FLASH.

Again, this flag is found in bbm.h and so should NOT be used in the
"nand_chip.options" field.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
index 69f7019..a4c82b4 100644
--- a/drivers/mtd/nand/davinci_nand.c
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -581,7 +581,7 @@
 	info->chip.chip_delay	= 0;
 	info->chip.select_chip	= nand_davinci_select_chip;
 
-	/* options such as NAND_USE_FLASH_BBT */
+	/* options such as NAND_BBT_USE_FLASH */
 	info->chip.bbt_options	= pdata->bbt_options;
 	/* options such as 16-bit widths */
 	info->chip.options	= pdata->options;