treewide: Replace Maximumm with Maximum in Kconfig symbol description

Replace Maximumm with Maximum in Kconfig symbol description, fix a typo.
No functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Michal Simek <michal.simek@amd.com>
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 185e834..2b7f5e5 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -216,7 +216,7 @@
 	 STM32 MCU.
 
 config SYS_MAX_FLASH_SECT
-	int "Maximumm number of sectors on a flash chip"
+	int "Maximum number of sectors on a flash chip"
 	depends on MTD_NOR_FLASH || FLASH_CFI_DRIVER
 	default 512