f2fs: fix spelling mistake: "extenstion" -> "extension"

Trivial fix to spelling mistake in extension list text
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/sysfs.c

@@ -147,13 +147,13 @@ static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
 		int len = 0, i;
 
 		len += snprintf(buf + len, PAGE_SIZE - len,
-						"cold file extenstion:\n");
+						"cold file extension:\n");
 		for (i = 0; i < cold_count; i++)
 			len += snprintf(buf + len, PAGE_SIZE - len, "%s\n",
 								extlist[i]);
 
 		len += snprintf(buf + len, PAGE_SIZE - len,
-						"hot file extenstion:\n");
+						"hot file extension:\n");
 		for (i = cold_count; i < cold_count + hot_count; i++)
 			len += snprintf(buf + len, PAGE_SIZE - len, "%s\n",
 								extlist[i]);