mtd: rawnand: sm_common: drop unexpected word 'is' in the comments

there is an unexpected word 'is' in the comments that need to be dropped

file: drivers/mtd/nand/raw/sm_common.c
line: 55

/* NOTE: This layout is is not compatabable with SmartMedia, */

changed to:

/* NOTE: This layout is not compatabable with SmartMedia, */
Signed-off-by: NJiang Jian <jiangjian@cdjrlc.com>
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220622160511.11679-1-jiangjian@cdjrlc.com

drivers/mtd/nand/raw/sm_common.c

@@ -52,7 +52,7 @@ static const struct mtd_ooblayout_ops oob_sm_ops = {
 	.free = oob_sm_ooblayout_free,
 };
 
-/* NOTE: This layout is is not compatabable with SmartMedia, */
+/* NOTE: This layout is not compatabable with SmartMedia, */
 /* because the 256 byte devices have page depenent oob layout */
 /* However it does preserve the bad block markers */
 /* If you use smftl, it will bypass this and work correctly */