mtd: subpagetest: fix wrong written check in function write_eraseblock2

Write size in function write_eraseblock2 is subpgsize * k.
It is wrong to check whether written is equal to subpgsize after each
mtd_write.

Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/tests/subpagetest.c

@@ -102,7 +102,7 @@ static int write_eraseblock2(int ebnum)
 		if (unlikely(err || written != subpgsize * k)) {
 			pr_err("error: write failed at %#llx\n",
 			       (long long)addr);
-			if (written != subpgsize) {
+			if (written != subpgsize * k) {
 				pr_err("  write size: %#x\n",
 				       subpgsize * k);
 				pr_err("  written: %#08zx\n",