mtd: sm_ftl: Fix typos in comments

Fix typo in the description of the 'succesfull'.

Signed-off-by: Bo Liu <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

drivers/mtd/sm_ftl.c

···
 	/* Update the FTL table */
 	zone->lba_to_phys_table[ftl->cache_block] = write_sector;
 
-	/* Write succesfull, so erase and free the old block */
+	/* Write successful, so erase and free the old block */
 	if (block_num > 0)
 		sm_erase_block(ftl, zone_num, block_num, 1);