UBI: fix s/then/than/ typos

	  The default value should be OK for SLC NAND flashes, NOR flashes and

	  other flashes which have eraseblock life-cycle 100000 or more.

	  However, in case of MLC NAND flashes which typically have eraseblock

	  life-cycle less then 10000, the threshold should be lessened (e.g.,

	  life-cycle less than 10000, the threshold should be lessened (e.g.,

	  to 128 or 256, although it does not have to be power of 2).

config MTD_UBI_BEB_RESERVE

 *

 * A: because when writing a sub-page, MTD still writes a full 2K page but the

 * bytes which are no relevant to the sub-page are 0xFF. So, basically, writing

 * 4x512 sub-pages is 4 times slower then writing one 2KiB NAND page. Thus, we

 * 4x512 sub-pages is 4 times slower than writing one 2KiB NAND page. Thus, we

 * prefer to use sub-pages only for EV and VID headers.

 *

 * As it was noted above, the VID header may start at a non-aligned offset.

 *

 * This function changes the contents of a logical eraseblock atomically. @buf

 * has to contain new logical eraseblock data, and @len - the length of the

 * data, which has to be aligned. The length may be shorter then the logical

 * data, which has to be aligned. The length may be shorter than the logical

 * eraseblock size, ant the logical eraseblock may be appended to more times

 * later on. This function guarantees that in case of an unclean reboot the old

 * contents is preserved. Returns zero in case of success and a negative error

 *

 * This function un-maps logical eraseblock @lnum and schedules the

 * corresponding physical eraseblock for erasure, so that it will eventually be

 * physically erased in background. This operation is much faster then the

 * physically erased in background. This operation is much faster than the

 * erase operation.

 *

 * Unlike erase, the un-map operation does not guarantee that the logical

 *

 * The main and obvious use-case of this function is when the contents of a

 * logical eraseblock has to be re-written. Then it is much more efficient to

 * first un-map it, then write new data, rather then first erase it, then write

 * first un-map it, then write new data, rather than first erase it, then write

 * new data. Note, once new data has been written to the logical eraseblock,

 * UBI guarantees that the old contents has gone forever. In other words, if an

 * unclean reboot happens after the logical eraseblock has been un-mapped and

 * case of success this function returns a positive value, in case of failure, a

 * negative error code is returned. The success return codes use the following

 * bits:

 *     o bit 0 is cleared: the first PEB (described by @seb) is newer then the

 *     o bit 0 is cleared: the first PEB (described by @seb) is newer than the

 *       second PEB (described by @pnum and @vid_hdr);

 *     o bit 0 is set: the second PEB is newer;

 *     o bit 1 is cleared: no bit-flips were detected in the newer LEB;

		if (cmp_res & 1) {

			/*

			 * This logical eraseblock is newer then the one

			 * This logical eraseblock is newer than the one

			 * found earlier.

			 */

			err = validate_vid_hdr(vid_hdr, sv, pnum);

 * @max: highest possible erase counter

 *

 * This function looks for a wear leveling entry with erase counter closest to

 * @max and less then @max.

 * @max and less than @max.

 */

static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max)

{