mtd: adjust kernel-docs to avoid Sphinx/kerneldoc warnings

./drivers/mtd/nand/nand_bbt.c:1: warning: no structured comments found
./include/linux/mtd/nand.h:785: ERROR: Unexpected indentation.
./drivers/mtd/nand/nand_base.c:449: WARNING: Definition list ends without a blank line; unexpected unindent.
./drivers/mtd/nand/nand_base.c:1161: ERROR: Unexpected indentation.
./drivers/mtd/nand/nand_base.c:1162: WARNING: Block quote ends without a blank line; unexpected unindent.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index b0524f8..c8988c0 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -442,10 +442,12 @@
  * specify how to write bad block markers to OOB (chip->block_markbad).
  *
  * We try operations in the following order:
+ *
  *  (1) erase the affected block, to allow OOB marker to be written cleanly
  *  (2) write bad block marker to OOB area of affected block (unless flag
  *      NAND_BBT_NO_OOB_BBM is present)
  *  (3) update the BBT
+ *
  * Note that we retain the first error encountered in (2) or (3), finish the
  * procedures, and dump the error in the end.
 */
@@ -1155,9 +1157,10 @@
  * @mtd: mtd info
  * @ofs: offset to start unlock from
  * @len: length to unlock
- * @invert: when = 0, unlock the range of blocks within the lower and
+ * @invert:
+ *        - when = 0, unlock the range of blocks within the lower and
  *                    upper boundary address
- *          when = 1, unlock the range of blocks outside the boundaries
+ *        - when = 1, unlock the range of blocks outside the boundaries
  *                    of the lower and upper boundary address
  *
  * Returs unlock status.