fs: FAT: Fix typo in FS_FAT_MAX_CLUSTSIZE description

Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
diff --git a/fs/fat/Kconfig b/fs/fat/Kconfig
index e7978aa..9bb11ea 100644
--- a/fs/fat/Kconfig
+++ b/fs/fat/Kconfig
@@ -14,7 +14,7 @@
 	  existing FAT filesystem partition.
 
 config FS_FAT_MAX_CLUSTSIZE
-	int "Set maximum possible clusersize"
+	int "Set maximum possible clustersize"
 	default 65536
 	depends on FS_FAT
 	help