mtd: rawnand: bcm47xx: fix spelling typo in comment

Fix spelling typo in comment.
Reported-by: k2ci <kernel-bot@kylinos.cn>
Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220905063232.1830197-1-13667453960@163.com

drivers/mtd/nand/raw/bcm47xxnflash/ops_bcm4706.c

@@ -14,7 +14,7 @@
 #include <linux/bcma/bcma.h>
 
 /* Broadcom uses 1'000'000 but it seems to be too many. Tests on WNDR4500 has
- * shown ~1000 retries as maxiumum. */
+ * shown ~1000 retries as maximum. */
 #define NFLASH_READY_RETRIES		10000
 
 #define NFLASH_SECTOR_SIZE		512